<p>There are two main usages of 了, as an aspect marker and as a modal particle.</p>
<hr>
<h3><em>Aspect marker</em>: expresses completion of an action</h3>
<p>In this case 了 can be used to produce a past tense. It typically follows immediately after the verb.</p>
<blockquote>
<p>V + 了 + Obj.</p>
<p>我买了一辆车 = I bought a car</p>
<p>我看了一部电影 = I watched a movie</p>
</blockquote>
<p>You can find the aspect marker 了 also after the object, when the object is strongly bound to its verb. This usually happens when the object is a place or in case of <em>verb-object compounds</em>, a.k.a. <a href="https://resources.allsetlearning.com/chinese/grammar/Separable_verb" rel="nofollow noreferrer">separable verbs</a>:</p>
<blockquote>
<p>V + Obj. + 了</p>
<p>我去台湾了 = I went to Taiwan</p>
<p>我吃饭了 = I ate</p>
</blockquote>
<p>In these cases, if you do place 了 between verb and object, the sentence &quot;hangs&quot;. It implies a follow-up. This is often used in subordinate constructions:</p>
<blockquote>
<p>我去了台湾（以后）= After I get to Taiwan, ...</p>
<p>我吃了饭（以后）= After I eat, ...</p>
</blockquote>
<hr>
<h3><em>Modal particle</em>: expresses <strong>change</strong></h3>
<p>The other usage of 了 as a modal particle is to express a change of state. It's found only at the end of the sentence.</p>
<blockquote>
<p>台湾我不想去了 = I don't want to go to Taiwan (anymore)</p>
<p>他的名字我想起来了 = I remember his name (now)</p>
</blockquote>
<p>A notable case of how the modal 了 affects the meaning of a sentence is:</p>
<blockquote>
<p>我知道 = I know</p>
<p>我知道<strong>了</strong> = I got it (I know it now, but I didn't knew it before)</p>
</blockquote>
<p>Among other use cases there is giving commands (imperative), as in:</p>
<blockquote>
<p>闭嘴了 = shut up! <br>
别闹我了= stop bothering me!<br>
我们走了 = let's go<br>
你关门了 = close the door!</p>
</blockquote>
<p>This makes sense because a command implies a change in what someone is doing: you're talking (status quo), but now I want you to <em>stop</em> (change); or the door is open (status quo), now I want you to close it (change).</p>
<p>Then, you can use 了 to express something you're going to do (future) or a decision you just made:</p>
<blockquote>
<p>我付钱了 = I'll pay!</p>
<p>As opposed to: <br>
钱我（已经）付了 = I've (already) paid</p>
</blockquote>
<p>The <em>要 ~ 了</em> construction also reflects this soon-to-change valence:</p>
<blockquote>
<p>飞机马上要落地了 = the plane is about to land</p>
<p>我快要毕业了 = I'm graduating soon</p>
</blockquote>
<p>Some additional examples to show the difference between past, status quo, change and future change with:</p>
<blockquote>
<p>今天下了雨 = it rained today (it's stopped now)<br>
下雨呢 = it rains (it was raining before too)<br>
下雨了 = it rains (now, while it wasn't before)<br>
今天要下雨了 = it's going to rain today <br></p>
</blockquote>
<p>Finally keep in mind that 了 doesn't necessarily indicate a change that's taking place right now. It can describe a situation that started in the past and hasn't ended yet (then it might appear together with the aspect 了):</p>
<blockquote>
<p>Change in the past (ending point):<br>
我等了 (ASP) 一个小时的车了 (MOD) = I waited the bus one hour (I'm not waiting anymore)</p>
<p>Change in the past (starting point) <br>
我等车（已经）一个小时了 (MOD) = I've been waiting the bus for one hour (the wait has started and I'm still waiting)</p>
</blockquote>

CC BY-SA 4.0
2015-11-16T11:28:17.783Z
2020-07-07T21:43:45.083Z
2020-07-07T21:43:45.083Z
blackgreen
<p>I think, after a long while I finally managed to figure out how to both wrap my head around this and how to actually explain how it works, as well - after 2 years (60 Ms) and two more courses of Chinese Mandarin later from my original post on the topic here:</p>

<p><a href="https://chinese.stackexchange.com/questions/22398/how-exactly-do-time-and-tense-work-in-mandarin-really">How exactly do time and &quot;tense&quot; work in Mandarin REALLY?</a></p>

<p>So here goes with what I've gathered, and feel free to challenge anything or even everything said here.</p>

<p>了 is <strong><em>NOT</em></strong> a tense marker. Period. That said, there are situations where it certainly <em>seems</em> to <em>look like one</em>, and that's where I think the confusion comes from. From multiple sources - including instructors and textbooks - if you have something like "I read a book" in English, meant as an answer to a question of the form "What did you do last night?" (Chinese: 你昨天晚上做什么？）, the answer is indeed given as you'd expect using "了":</p>

<ul>
<li>Person A: 你昨天晚上做什么？</li>
<li>Person B: 我看<strong>了</strong>一本书。</li>
</ul>

<p>And indeed if we did not include it and just said 我看一本书, it would sound as strange as if I were to say in English, "I read (pronounced <em>reed</em>) a book" as a response to the given question. And it is also true that in this context it <em>effectively</em> serves the same function of harmonizing with the past nature of the action in question.</p>

<p>The key point though in understanding it is that the <em>logic</em> of 了 in how it does this is different from that of how the "-ed" ending (here heard in pronunciation but masked by the irregularities and vagaries of English orthography) in English does it. "-ed" <em>directly</em> marks past time. However 了 can be interpreted in at least two ways, depending on what model of grammar you want to use as in any analysis of human language there may be and are often different conceptual or theoretical models of how a language functions that can explain the phenomena within it and many arguments are waged in linguistic studies as to which are the "best" models in question: keep in mind that "grammar", as we call it, is not so much a rule book that was written up by the language's "inventors", i.e. its users, but rather that grammars, like dictionaries, are attempts by language <em>scholars</em> to <em>describe</em> how language operates in detail, and thus it can vary from scholar to scholar how it may be understood.</p>

<p>With that out of the way, we will proceed. The first model is perhaps the one most commonly cited, and that is that "了" is an <em>aspect marker</em> that marks the <em>perfective aspect</em>, that is, the fact of something having been completed, finalized, or brought to its end. In this case, what the sentence then says is to assert as a fact that the reading of the book is completed. This, without further indicators, <em>implies</em> that it must have been in the past, because of how that causality works in the physical universe: the bringing-to-completion of something is caused by things-that-bring-it-to-completion, and causes always precede their effects, thus the "reading process" - the stuff that was needed to bring about that culmination - <em>must have</em>, by <em>inference</em>, occurred in the past.</p>

<p>The second model (see here: <a href="https://chinese.stackexchange.com/a/22407/16171">https://chinese.stackexchange.com/a/22407/16171</a>) is a bit different in how it conceptualizes 了 but it follows a similar logic. In this interpretation 了 is a marker for the <em>realis mood</em>, meaning that the reading of the book is something that is an actual state of affairs in the world, not, say, a hypothetical. With regard to an action taken, like "reading a book", the only way this can be actual is if the reading is either being done right now, or it was done in the past, because (at least cognitively, not wanting to drag in deep philosophical and even physics-related arguments about the ontological status of the future) only the past and present are real, the future is hypothetical or unreal (the mood that expresses this is called "irrealis" in linguistic terminology). By elimination of the possibility of the reading happening in the present (since you see I am not engaged in it), then it follows (this form of a logical argument is called a <em>disjunctive syllogism</em> - which goes: <em>P or Q. Not P. Therefore, Q.</em>) that it occurred in the past.</p>

<p>Whatever the model we choose to use to understand this bit of language, we arrive at the conclusion the action was in the past, and that the past-ness of the action is indeed communicated by 了. However, it <em>gets there by a different route</em> than English does, and understanding both that route <em>and</em> how it gets to this outcome <em>and</em> moreover acknowledging that it <em>does</em> still lead to the same outcome, are all important to properly understanding the usage of this important basic word. Because if we interpret it as having <em>no</em> relevance to time, we will be plagued with suspicion about the fact that</p>

<ul>
<li>我看了一本书</li>
</ul>

<p>is a valid way to answer</p>

<ul>
<li>你昨天晚上做什么？</li>
</ul>

<p><em>AND</em> if we interpret it as being a tense marker like in English, we will not be able to understand how a construction like</p>

<ul>
<li>我明天看了一本书</li>
</ul>

<p>could make any sense, as if it is tense, that sentence is literally a logical contradiction saying something is simultaneously in both the future (tomorrow) and the past (misunderstood 了).</p>

<p>The aspect theory seems to be the more commonly used one, but what's often missing it seems is an explication of the logic of how this <em>does relate</em> to time even though and while importantly pointing out that the <em>direct referent</em> is not time, and I think that makes it hard for English speakers to make the transition because they will be naturally inclined (as indeed one of the papers referenced in the second link talks about) to be <em>focused on</em> the <em>time</em> aspect and will rightly pick it out, but the <em>base concept</em> is not time, and the proper explanation must be able to accommodate both instead of just saying it's not a tense marker and then leaving it at that and leaving the individual in question hanging.</p>

CC BY-SA 4.0
2018-11-08T13:22:05.643Z
Finally, someone got the message I was preaching. :)
coobit
CC BY-SA 4.0
2018-11-07T08:55:08.043Z
2018-11-07T08:55:08.043Z
The_Sympathizer
<p>actually,
the tense maker 了has two different type.
that concept is equal to the conjunction of verb.
the first type of the 了1 , common condition is used like suffix just adding after the verb.
that means perfective maker. the action is completed. also like present tense as well as
past tense.</p>

<p>the second type of 了2 ，is adding to the end 
of the sentence, for instance, "他突然之间就跑了" that means emphasising the effect to present or probably cause a new case to present times.  and aboselusly, is prefect aspect.  so, the decision of adopting past perfect or present perfect is depends the adverb。
我离开上海了。（perfect tense）
我离开了上海 。   （present tense or past tense）</p>

CC BY-SA 4.0
2019-09-29T02:41:04.993Z
2019-09-29T02:41:04.993Z
王大侠
<p>了 is often used in the past tense, but should not be confused with 过. 了 implies a recent change that might still be in effect, while 过 is further in the past and is no longer in effect.</p>
<p>Example:</p>
<blockquote>
<p>我坐了 I have sat down (and am still sitting)</p>
<p>我坐过 I have sat down (and am no longer sitting)</p>
</blockquote>
<p>You can also use it with 太 to put emphasis on something.</p>
<p>Example:</p>
<blockquote>
<p>太冷了 Too cold!</p>
</blockquote>

CC BY-SA 3.0
2014-11-24T16:08:17.560Z
In your `太冷了` example, does `了` have any effect on the tense of that statement?
Cocowalla
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2014-11-26T22:05:00.040Z
@Cocowalla The way I understand it, you have to add 了, otherwise it will sound weird to native speakers.
Friso
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2014-11-24T15:10:12.433Z
2014-11-24T15:10:12.433Z
2020-06-17T09:50:11.587Z
Friso
<p>for someone who new in Chinese, when you see 了, just seem as "it's already done"
it's suit for 70% situation, and in this situation, it can be ignored, if you delete 了，the meaning doesn't change, it's just emphasize "its done, its done, its done"</p>

<p>if you feel the meaning is strange, than …. just ignore it. in almost 99% of situation
the meaning wont change, if you delete 了 in sentense</p>

CC BY-SA 4.0
2019-10-31T02:54:42.457Z
2019-10-31T02:54:42.457Z
name
<p>I read <a href="https://www.echineselearning.com/blog/usages-of-commonly-used-chinese-particle?ecl=ptEEEEEE&amp;pla=StackExchange20181107usele" rel="nofollow noreferrer">Chinese Grammar Hack: The Many Uses And Rules of 了 (le)</a> in eChineseLearning blogpage, and it introduced 3 main uses of “了 (le)”:</p>

<ol>
<li>The completion of an event
A basic meaning of “了 (le)” is to indicate the completion of the event. It is not quite the same as the English past tense. In the English past tense, whether it is representative of modality or event, the past tense should be used as long as the event is in the past. However, the Chinese character “了 (le)” is used in past events instead of past modalities.</li>
</ol>

<p>Tā yǐqián hěn tǎoyàn tā. </p>

<p>他以前很讨厌她。</p>

<p>He hated her in the past.</p>

<p>VS.
Tā chī wán le fàn. </p>

<p>他吃完了饭。</p>

<p>He had a meal.</p>

<p>As we can see in the first sentence, “hated her” shows a state, not the completion of a specific activity. Therefore, we don’t use “了 (le)” after the verb, or at all in this first example.</p>

<p>As for the second example, we learn of an activity that has been done, so we use “了 (le).”</p>

<ol start="2">
<li>To describe a sequence of events
Secondly, “了 (le)” shows the sequence in which two actions occur.</li>
</ol>

<p>Wǒ xǐ le zǎo jiù shàngchuáng shuìjiào le.</p>

<p>我洗了澡就上床睡觉了.</p>

<p>After taking a shower, I went to bed.</p>

<ol start="3">
<li>Thirdly, as a sign of major events
Often, a sentence contains more than one event. We can divide these events into main events and secondary events, so we only need to use “了 (le)” in the main event instead of using it again in the secondary event.</li>
</ol>

<p>Tā rèxīn de bāng wǒ sǎo le dì.</p>

<p>她热心地帮我扫了地.</p>

<p>She helped me eagerly to sweep the floor.</p>

<p>Examples:</p>

<p>Tā cānjiā le zhècì huódòng.</p>

<p>他参加了这次活动。</p>

<p>He took part in this activity.</p>

<p>I think it may help you.</p>

CC BY-SA 4.0
2018-11-07T07:29:27.877Z
2018-11-16T01:13:55.907Z
2018-11-16T01:13:55.907Z
RosalieJones
<p>To make some corrections to The_Sympathizer answer.</p>

<blockquote>
  <p>the only way this can be actual is if the reading is either being done right now, or it was done in the past, only the past and present
  are real, the future is hypothetical or unreal</p>
</blockquote>

<p>Mostly true, BUT...  there are actually 2 realis markers. </p>

<ol>
<li>Verbal了 which is <strong>relative</strong> realis marker</li>
<li>Sentencial 了 which is <strong>absolute</strong> realis marker.</li>
</ol>

<p>You can and must use verbal 了 in future context to mark that "X will be done only after Y becomes factual (real)".
For example:
If or when Y is true, X will follow. </p>

<blockquote>
  <p>吃完了午飯就走
  that is Y = "吃完午飯" and X = "走"</p>
</blockquote>

<p>this expample can be translated as: </p>

<p><em>"When(了) eating(吃午飯) is finished(完), I will(就) leave(走)."</em></p>

<p>Here I put 了 next to "WHEN" to indicate that 了 marks relative realis condition and WHEN is the best way to translay 了 here. So another translation could be : </p>

<p><em>"When in real life eating is over, I will leave."</em></p>

<p>The sentencial 了 marks absolute factuality and can't be used in Future contexta.</p>

CC BY-SA 4.0
2018-11-08T13:33:16.430Z
2018-11-08T13:33:16.430Z
coobit
<p>The particle 了 (le) suggests a completed action. For example,</p>

<p>吃饭了 (chi fan le), finished eating.</p>

CC BY-SA 3.0
2011-12-13T22:35:30.503Z
I understand that, but from other uses I've seen it appears to be more complex than that
Cocowalla
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2011-12-13T22:36:43.157Z
@Cocowalla: Yes, there are more complex usages. I've given you the simplest one.
Tom Au
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2011-12-14T10:49:32.353Z
@Cocowalla Chi Fan Le DO NOT means finished eating. Instead that, like a mom want to call for her children to eat: "孩子们，吃饭了"(boys, time for meal)
Alex Chen
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2011-12-14T11:03:28.687Z
@AntiGameZ what about `nǐ chī le ma?` - does that not mean, `have you eaten?`
Cocowalla
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2011-12-14T11:08:10.503Z
@Cocowalla no, 了 in 你吃了吗 means have you eaten, which suggests a completed action.
Alex Chen
CC BY-SA 3.0
2011-12-14T11:32:18.407Z
@AntiGameZ so, `你吃了吗` *does* mean `have you eaten?`, but `吃了` *does not* mean 'I have eaten'?
Cocowalla
CC BY-SA 3.0
2011-12-14T11:39:11.330Z
@Cocowalla 了 in 你吃了吗 and 吃了 have the same mean that the eat action has completed. However, 吃饭了, like kazer took for instance  in his answer, means let's eat.
Alex Chen
CC BY-SA 3.0
2011-12-14T11:46:13.673Z
Hmm... confusing, but I finally get you :)  Is this something very specific to `吃饭了`, or is this part of some wider 'rule' on the usage of `了`?
Cocowalla
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2011-12-14T14:04:36.763Z
@Cocowalla In this context `了` is indicating a change in time. It can also be used to indicate a change in the weather or in seasons. E.g., `春天了`, `天气暖和了`, `三点半了`. In a similar context, `了` can also be used to indicate a change of situation. E.g., `现在我不是老师了`.
Krazer
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2011-12-13T22:29:08.973Z
2015-11-12T21:02:11.407Z
2015-11-12T21:02:11.407Z
Tom Au
<p>Usually 了 is used to indicate past tense (or the completion of). Such as: </p>

<blockquote>
  <p>我吃了</p>
  
  <p>了 is added to the end of the sentence that change the statement to past tense. You can add 过 before 了 to add emphasis. </p>
  
  <p>E.g., 我吃了 (I ate) vs. 我吃过了 (I have (already) eaten.)</p>
</blockquote>

<p>but 了 may be used for different reasons, some of which have nothing to do with past tense. </p>

<p>With imperatives, it adds urgency: </p>

<blockquote>
  <p>走了, 走了 </p>
  
  <p>(Let's) go, (let's) go.</p>
</blockquote>

<p>So, a negative imperative becomes a warning:</p>

<blockquote>
  <p>别说话</p>
  
  <p>(Keep quiet.)</p>
</blockquote>

<p>vs.</p>

<blockquote>
  <p>别说话了</p>
  
  <p>(I'm warning you [to]) stop talking!</p>
</blockquote>

<p>With certain modifiers you can use 了 to indicate future tense:</p>

<blockquote>
  <p>天就要下雨了（it's raining soon)</p>
</blockquote>

<p>Here 要 (an auxiliary verb) indicates future tense, by implying the sense of "going to do (something)." 會 is another auxiliary verb that does the same thing, but in the sense of "intending to do (something)."</p>

<p>了 when used after an adjective or noun, conveys the meaning "has become"</p>

<blockquote>
  <p>我餓 (I'm hungry)</p>
</blockquote>

<p>vs.</p>

<blockquote>
  <p>我餓了 (I became hungry)</p>
</blockquote>

<p>Here 了 expresses a clear (change of) state.  </p>

<p>了 can also be used to express excessiveness.</p>

<blockquote>
  <p>太 + (stative verb/adjective/noun) + 了. E.g., 太冷了.</p>
  
  <p>(stative verb/adjective/noun) + 极了. E.g., 热极了.</p>
  
  <p>可 + (stative verb/adjective/noun) + 了. E.g., 可难了.</p>
</blockquote>

<p>太 can be used without 了.  If omitted, the tone can sound rather rough.  </p>

CC BY-SA 3.0
2012-01-03T23:35:28.560Z
I think you can also use 了 when expressing surprise or emphasis. e.g. 太好了! Although in this case its use is within an idiomatic expression and should therefore be learnt as a unit.
jaffa
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2011-12-13T22:37:42.160Z
"With certain modifiers you can use 了 to indicate future tense" - yikes! This really is going to take some time to get my head round :}
Cocowalla
CC BY-SA 3.0
2011-12-13T23:09:03.717Z
Basically if 要/會/就/快 appears before the verb or any time specification appears before the subject (except with 快), 了 can be used to indicate future tense. But with 快, you can't use a construct of time like the word "yesterday." There are other verbs when used as a modal do the same/similar things, but these are usually the most common ones.
Krazer
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2011-12-14T06:17:35.607Z
I think sometimes the 了 is used just because it sounds right.
Matthew Rudy 马泰
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2011-12-13T22:34:18.777Z
2011-12-14T14:05:51.473Z
2011-12-14T14:05:51.473Z
Krazer
<p>I struggle a bit to get my head around tenses in Mandarin, and in particular when I need to use 了 (le).</p>

<p>Do you have any tips, examples or resources to help me out with this?</p>

<grammar><mandarin>
Tense and use of 了
# Tense and use of 了

(Asked by: username_0 on 2011-12-13)

I struggle a bit to get my head around tenses in Mandarin, and in particular when I need to use 了 (le).

Do you have any tips, examples or resources to help me out with this?

**Tags:** grammar, mandarin


---

## 9 answers

### Answer by username_10 on 2011-12-13. Score: 30 | Accepted answer

Usually 了 is used to indicate past tense (or the completion of). Such as:

> 我吃了
>
> 了 is added to the end of the sentence that change the statement to past tense. You can add 过 before 了 to add emphasis.
>
> E.g., 我吃了 (I ate) vs. 我吃过了 (I have (already) eaten.)

but 了 may be used for different reasons, some of which have nothing to do with past tense.

With imperatives, it adds urgency:

> 走了, 走了
>
> (Let's) go, (let's) go.

So, a negative imperative becomes a warning:

> 别说话
>
> (Keep quiet.)

vs.

> 别说话了
>
> (I'm warning you [to]) stop talking!

With certain modifiers you can use 了 to indicate future tense:

> 天就要下雨了（it's raining soon)

Here 要 (an auxiliary verb) indicates future tense, by implying the sense of "going to do (something)." 會 is another auxiliary verb that does the same thing, but in the sense of "intending to do (something)."

了 when used after an adjective or noun, conveys the meaning "has become"

> 我餓 (I'm hungry)

vs.

> 我餓了 (I became hungry)

Here 了 expresses a clear (change of) state.

了 can also be used to express excessiveness.

> 太 + (stative verb/adjective/noun) + 了. E.g., 太冷了.
>
> (stative verb/adjective/noun) + 极了. E.g., 热极了.
>
> 可 + (stative verb/adjective/noun) + 了. E.g., 可难了.

太 can be used without 了. If omitted, the tone can sound rather rough.

> **Comments:**
> **username_0**: "With certain modifiers you can use 了 to indicate future tense" - yikes! This really is going to take some time to get my head round :}  
> **username_10**: Basically if 要/會/就/快 appears before the verb or any time specification appears before the subject (except with 快), 了 can be used to indicate future tense. But with 快, you can't use a construct of time like the word "yesterday." There are other verbs when used as a modal do the same/similar things, but these are usually the most common ones.  
> **username_12**: I think sometimes the 了 is used just because it sounds right.  
> **username_11**: I think you can also use 了 when expressing surprise or emphasis. e.g. 太好了! Although in this case its use is within an idiomatic expression and should therefore be learnt as a unit.  

---

### Answer by username_1 on 2015-11-16. Score: 8

There are two main usages of 了, as an aspect marker and as a modal particle.

---

### *Aspect marker*: expresses completion of an action

In this case 了 can be used to produce a past tense. It typically follows immediately after the verb.

> V + 了 + Obj.
>
> 我买了一辆车 = I bought a car
>
> 我看了一部电影 = I watched a movie

You can find the aspect marker 了 also after the object, when the object is strongly bound to its verb. This usually happens when the object is a place or in case of *verb-object compounds*, a.k.a. [separable verbs](https://resources.allsetlearning.com/chinese/grammar/Separable_verb):

> V + Obj. + 了
>
> 我去台湾了 = I went to Taiwan
>
> 我吃饭了 = I ate

In these cases, if you do place 了 between verb and object, the sentence "hangs". It implies a follow-up. This is often used in subordinate constructions:

> 我去了台湾（以后）= After I get to Taiwan, ...
>
> 我吃了饭（以后）= After I eat, ...

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### *Modal particle*: expresses **change**

The other usage of 了 as a modal particle is to express a change of state. It's found only at the end of the sentence.

> 台湾我不想去了 = I don't want to go to Taiwan (anymore)
>
> 他的名字我想起来了 = I remember his name (now)

A notable case of how the modal 了 affects the meaning of a sentence is:

> 我知道 = I know
>
> 我知道**了** = I got it (I know it now, but I didn't knew it before)

Among other use cases there is giving commands (imperative), as in:

> 闭嘴了 = shut up!   
> 别闹我了= stop bothering me!  
> 我们走了 = let's go  
> 你关门了 = close the door!

This makes sense because a command implies a change in what someone is doing: you're talking (status quo), but now I want you to *stop* (change); or the door is open (status quo), now I want you to close it (change).

Then, you can use 了 to express something you're going to do (future) or a decision you just made:

> 我付钱了 = I'll pay!
>
> As opposed to:   
> 钱我（已经）付了 = I've (already) paid

The *要 ~ 了* construction also reflects this soon-to-change valence:

> 飞机马上要落地了 = the plane is about to land
>
> 我快要毕业了 = I'm graduating soon

Some additional examples to show the difference between past, status quo, change and future change with:

> 今天下了雨 = it rained today (it's stopped now)  
> 下雨呢 = it rains (it was raining before too)  
> 下雨了 = it rains (now, while it wasn't before)  
> 今天要下雨了 = it's going to rain today

Finally keep in mind that 了 doesn't necessarily indicate a change that's taking place right now. It can describe a situation that started in the past and hasn't ended yet (then it might appear together with the aspect 了):

> Change in the past (ending point):  
> 我等了 (ASP) 一个小时的车了 (MOD) = I waited the bus one hour (I'm not waiting anymore)
>
> Change in the past (starting point)   
> 我等车（已经）一个小时了 (MOD) = I've been waiting the bus for one hour (the wait has started and I'm still waiting)


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### Answer by username_2 on 2018-11-07. Score: 6

I think, after a long while I finally managed to figure out how to both wrap my head around this and how to actually explain how it works, as well - after 2 years (60 Ms) and two more courses of Chinese Mandarin later from my original post on the topic here:

[How exactly do time and "tense" work in Mandarin REALLY?](https://chinese.stackexchange.com/questions/22398/how-exactly-do-time-and-tense-work-in-mandarin-really)

So here goes with what I've gathered, and feel free to challenge anything or even everything said here.

了 is ***NOT*** a tense marker. Period. That said, there are situations where it certainly *seems* to *look like one*, and that's where I think the confusion comes from. From multiple sources - including instructors and textbooks - if you have something like "I read a book" in English, meant as an answer to a question of the form "What did you do last night?" (Chinese: 你昨天晚上做什么？）, the answer is indeed given as you'd expect using "了":

* Person A: 你昨天晚上做什么？
* Person B: 我看**了**一本书。

And indeed if we did not include it and just said 我看一本书, it would sound as strange as if I were to say in English, "I read (pronounced *reed*) a book" as a response to the given question. And it is also true that in this context it *effectively* serves the same function of harmonizing with the past nature of the action in question.

The key point though in understanding it is that the *logic* of 了 in how it does this is different from that of how the "-ed" ending (here heard in pronunciation but masked by the irregularities and vagaries of English orthography) in English does it. "-ed" *directly* marks past time. However 了 can be interpreted in at least two ways, depending on what model of grammar you want to use as in any analysis of human language there may be and are often different conceptual or theoretical models of how a language functions that can explain the phenomena within it and many arguments are waged in linguistic studies as to which are the "best" models in question: keep in mind that "grammar", as we call it, is not so much a rule book that was written up by the language's "inventors", i.e. its users, but rather that grammars, like dictionaries, are attempts by language *scholars* to *describe* how language operates in detail, and thus it can vary from scholar to scholar how it may be understood.

With that out of the way, we will proceed. The first model is perhaps the one most commonly cited, and that is that "了" is an *aspect marker* that marks the *perfective aspect*, that is, the fact of something having been completed, finalized, or brought to its end. In this case, what the sentence then says is to assert as a fact that the reading of the book is completed. This, without further indicators, *implies* that it must have been in the past, because of how that causality works in the physical universe: the bringing-to-completion of something is caused by things-that-bring-it-to-completion, and causes always precede their effects, thus the "reading process" - the stuff that was needed to bring about that culmination - *must have*, by *inference*, occurred in the past.

The second model (see here: <https://chinese.stackexchange.com/a/22407/16171>) is a bit different in how it conceptualizes 了 but it follows a similar logic. In this interpretation 了 is a marker for the *realis mood*, meaning that the reading of the book is something that is an actual state of affairs in the world, not, say, a hypothetical. With regard to an action taken, like "reading a book", the only way this can be actual is if the reading is either being done right now, or it was done in the past, because (at least cognitively, not wanting to drag in deep philosophical and even physics-related arguments about the ontological status of the future) only the past and present are real, the future is hypothetical or unreal (the mood that expresses this is called "irrealis" in linguistic terminology). By elimination of the possibility of the reading happening in the present (since you see I am not engaged in it), then it follows (this form of a logical argument is called a *disjunctive syllogism* - which goes: *P or Q. Not P. Therefore, Q.*) that it occurred in the past.

Whatever the model we choose to use to understand this bit of language, we arrive at the conclusion the action was in the past, and that the past-ness of the action is indeed communicated by 了. However, it *gets there by a different route* than English does, and understanding both that route *and* how it gets to this outcome *and* moreover acknowledging that it *does* still lead to the same outcome, are all important to properly understanding the usage of this important basic word. Because if we interpret it as having *no* relevance to time, we will be plagued with suspicion about the fact that

* 我看了一本书

is a valid way to answer

* 你昨天晚上做什么？

*AND* if we interpret it as being a tense marker like in English, we will not be able to understand how a construction like

* 我明天看了一本书

could make any sense, as if it is tense, that sentence is literally a logical contradiction saying something is simultaneously in both the future (tomorrow) and the past (misunderstood 了).

The aspect theory seems to be the more commonly used one, but what's often missing it seems is an explication of the logic of how this *does relate* to time even though and while importantly pointing out that the *direct referent* is not time, and I think that makes it hard for English speakers to make the transition because they will be naturally inclined (as indeed one of the papers referenced in the second link talks about) to be *focused on* the *time* aspect and will rightly pick it out, but the *base concept* is not time, and the proper explanation must be able to accommodate both instead of just saying it's not a tense marker and then leaving it at that and leaving the individual in question hanging.

> **Comments:**
> **username_3**: Finally, someone got the message I was preaching. :)  

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### Answer by username_4 on 2019-09-29. Score: 2

actually,
the tense maker 了has two different type.
that concept is equal to the conjunction of verb.
the first type of the 了1 , common condition is used like suffix just adding after the verb.
that means perfective maker. the action is completed. also like present tense as well as
past tense.

the second type of 了2 ，is adding to the end
of the sentence, for instance, "他突然之间就跑了" that means emphasising the effect to present or probably cause a new case to present times. and aboselusly, is prefect aspect. so, the decision of adopting past perfect or present perfect is depends the adverb。
我离开上海了。（perfect tense）
我离开了上海 。 （present tense or past tense）


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### Answer by username_5 on 2014-11-24. Score: 1

了 is often used in the past tense, but should not be confused with 过. 了 implies a recent change that might still be in effect, while 过 is further in the past and is no longer in effect.

Example:

> 我坐了 I have sat down (and am still sitting)
>
> 我坐过 I have sat down (and am no longer sitting)

You can also use it with 太 to put emphasis on something.

Example:

> 太冷了 Too cold!

> **Comments:**
> **username_0**: In your `太冷了` example, does `了` have any effect on the tense of that statement?  
> **username_5**: @username_0 The way I understand it, you have to add 了, otherwise it will sound weird to native speakers.  

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### Answer by username_6 on 2019-10-31. Score: 1

for someone who new in Chinese, when you see 了, just seem as "it's already done"
it's suit for 70% situation, and in this situation, it can be ignored, if you delete 了，the meaning doesn't change, it's just emphasize "its done, its done, its done"

if you feel the meaning is strange, than …. just ignore it. in almost 99% of situation
the meaning wont change, if you delete 了 in sentense


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### Answer by username_7 on 2018-11-07. Score: 1

I read [Chinese Grammar Hack: The Many Uses And Rules of 了 (le)](https://www.echineselearning.com/blog/usages-of-commonly-used-chinese-particle?ecl=ptEEEEEE&pla=StackExchange20181107usele) in eChineseLearning blogpage, and it introduced 3 main uses of “了 (le)”:

1. The completion of an event
   A basic meaning of “了 (le)” is to indicate the completion of the event. It is not quite the same as the English past tense. In the English past tense, whether it is representative of modality or event, the past tense should be used as long as the event is in the past. However, the Chinese character “了 (le)” is used in past events instead of past modalities.

Tā yǐqián hěn tǎoyàn tā.

他以前很讨厌她。

He hated her in the past.

VS.
Tā chī wán le fàn.

他吃完了饭。

He had a meal.

As we can see in the first sentence, “hated her” shows a state, not the completion of a specific activity. Therefore, we don’t use “了 (le)” after the verb, or at all in this first example.

As for the second example, we learn of an activity that has been done, so we use “了 (le).”

2. To describe a sequence of events
   Secondly, “了 (le)” shows the sequence in which two actions occur.

Wǒ xǐ le zǎo jiù shàngchuáng shuìjiào le.

我洗了澡就上床睡觉了.

After taking a shower, I went to bed.

3. Thirdly, as a sign of major events
   Often, a sentence contains more than one event. We can divide these events into main events and secondary events, so we only need to use “了 (le)” in the main event instead of using it again in the secondary event.

Tā rèxīn de bāng wǒ sǎo le dì.

她热心地帮我扫了地.

She helped me eagerly to sweep the floor.

Examples:

Tā cānjiā le zhècì huódòng.

他参加了这次活动。

He took part in this activity.

I think it may help you.


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### Answer by username_3 on 2018-11-08. Score: 0

To make some corrections to The\_Sympathizer answer.

> the only way this can be actual is if the reading is either being done right now, or it was done in the past, only the past and present
> are real, the future is hypothetical or unreal

Mostly true, BUT... there are actually 2 realis markers.

1. Verbal了 which is **relative** realis marker
2. Sentencial 了 which is **absolute** realis marker.

You can and must use verbal 了 in future context to mark that "X will be done only after Y becomes factual (real)".
For example:
If or when Y is true, X will follow.

> 吃完了午飯就走
> that is Y = "吃完午飯" and X = "走"

this expample can be translated as:

*"When(了) eating(吃午飯) is finished(完), I will(就) leave(走)."*

Here I put 了 next to "WHEN" to indicate that 了 marks relative realis condition and WHEN is the best way to translay 了 here. So another translation could be :

*"When in real life eating is over, I will leave."*

The sentencial 了 marks absolute factuality and can't be used in Future contexta.


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### Answer by username_8 on 2011-12-13. Score: 0

The particle 了 (le) suggests a completed action. For example,

吃饭了 (chi fan le), finished eating.

> **Comments:**
> **username_0**: I understand that, but from other uses I've seen it appears to be more complex than that  
> **username_8**: @username_0: Yes, there are more complex usages. I've given you the simplest one.  
> **username_9**: @username_0 Chi Fan Le DO NOT means finished eating. Instead that, like a mom want to call for her children to eat: "孩子们，吃饭了"(boys, time for meal)  
> **username_0**: @AntiGameZ what about `nǐ chī le ma?` - does that not mean, `have you eaten?`  
> **username_9**: @username_0 no, 了 in 你吃了吗 means have you eaten, which suggests a completed action.  
> **username_0**: @AntiGameZ so, `你吃了吗` *does* mean `have you eaten?`, but `吃了` *does not* mean 'I have eaten'?  
> **username_9**: @username_0 了 in 你吃了吗 and 吃了 have the same mean that the eat action has completed. However, 吃饭了, like kazer took for instance  in his answer, means let's eat.  
> **username_0**: Hmm... confusing, but I finally get you :)  Is this something very specific to `吃饭了`, or is this part of some wider 'rule' on the usage of `了`?  
> **username_10**: @username_0 In this context `了` is indicating a change in time. It can also be used to indicate a change in the weather or in seasons. E.g., `春天了`, `天气暖和了`, `三点半了`. In a similar context, `了` can also be used to indicate a change of situation. E.g., `现在我不是老师了`.  

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