<p>I will take advantage of this question to write a summary of the <strong>sentence-final 了</strong> or <strong>modal 了</strong>, which occurs at the <em>end of a sentence</em>. [Also, the <strong>sentence-final 了</strong> should not be confused with the <a href="https://chinese.stackexchange.com/a/40507/25265"><strong>perfective or aspectual 了</strong></a>, which occurs just <em>after a verb</em> and marks a <em>bounded action</em>.]</p>
<p>From Charles N. Li, Sandra A. Thompson - <em>Mandarin Chinese: A Functional Reference Grammar</em>, they consider the sentence-final 了 to signal a <strong>Currently Relevant State</strong> (CRS), that is, <em>了 marks a state of affairs with a current relevance to the particular situation.</em> Although in the book they argue otherwise, I believe in all cases there is always an inherent <em>change of state</em>. We can understand:</p>
<ul>
<li><p><em>Currently</em>: refers to the particular situation (and not necessarily to the present or even real situation). For example:</p>
<blockquote>
<p>前一个星期票都卖光<strong>了</strong>。</p>
<p>One week ago, all the tickets were sold out (&quot;All the tickets were sold out&quot; is a Currently Relevant State respect to &quot;One week ago&quot;).</p>
</blockquote>
<blockquote>
<p>我是法国人就不会说这么坏的法文<strong>了</strong>。</p>
<p>If I were French, then I wouldn't be speaking such bad French (&quot;I wouldn't be speaking such bad French&quot; is a Currently Relevant State respect to &quot;If I were French&quot;).</p>
</blockquote>
</li>
<li><p><em>Relevance</em>: the state of affairs given by the sentence is relevant for the speaker and the hearer in the context of the particular situation.</p>
</li>
<li><p><em>State</em>: refers to the state of affairs signaled by the sentence with 了. It can be classified into the following possibilities:</p>
<ol>
<li><p>(&quot;Simple&quot;) <strong>change of state</strong>: Previously the state of affair did not hold, but now currently holds (thus, it is relevant). For example:</p>
<blockquote>
<p>他知道那个消息<strong>了</strong>。</p>
<p>He knows about that piece of news (he did not before).</p>
</blockquote>
<blockquote>
<p>已经四点<strong>了</strong>。</p>
<p>It's already four o'clock (it was not before).</p>
</blockquote>
<p>But also, the change could be about the state of knowledge of the speaker or the hearer. For example:</p>
<blockquote>
<p>下雨<strong>了</strong>。</p>
<p>It's raining (either it was not raining before or the speaker has just realized it).</p>
</blockquote>
<blockquote>
<p>Q: 她怎么样？A: 她做教授<strong>了</strong>。</p>
<p>Q: How is she? A: She has become a professor (the first person did not knew about this state).</p>
</blockquote>
</li>
<li><p><strong>Corrects a wrong assumption</strong>: The current situation contradicts an assumption. For example:</p>
<blockquote>
<p>[A kid who does not want to eat his/her food, but the same food as the adults. Her mother says:]</p>
<p>一样的<strong>了</strong>。</p>
<p>It's the same！(You are wrong in thinking you are eating something different).</p>
</blockquote>
</li>
<li><p><strong>Reports current progress</strong>: the speaker uses 了 to show concern for the progress of an state. For example:</p>
<blockquote>
<p>[School official registering children:]</p>
<p>你几岁？</p>
<p>How old are you?</p>
</blockquote>
<blockquote>
<p>[A relative:]</p>
<p>你几岁<strong>了</strong>？</p>
<p>How old are you?</p>
</blockquote>
</li>
<li><p><strong>What happens next</strong>: the current state of affairs is relevant for what can happen on the following.</p>
<blockquote>
<p>[Someone is arriving:]</p>
<p>他进来了。</p>
<p>He is coming in.</p>
</blockquote>
</li>
<li><p><strong>Announces the finality of a statement</strong>: Introduces the statement into the current situation. Otherwise the sentence might sound incomplete, requiring some other justification to make it relevant. For example:</p>
<blockquote>
<p>[As an answer to why the speaker did not study in a university:]</p>
<p>因为那里学费太贵。</p>
<p>Because the tuition fees are too expensive there (the situation was already introduced).</p>
</blockquote>
<blockquote>
<p>[One student complaints to another:]</p>
<p>学费太贵<strong>了</strong>!</p>
<p>The tuition fees are really too expensive!</p>
</blockquote>
</li>
</ol>
</li>
</ul>

CC BY-SA 4.0
2020-09-07T20:39:09.977Z
2020-09-07T20:47:53.453Z
2020-09-07T20:47:53.453Z
Puco4
<p>Judging from <a href="http://www.xuexila.com/english/way/c39349.html" rel="nofollow noreferrer">this webpage</a>, it's a translation from the English:</p>
<blockquote>
<p>Stay home so you can answer the phone.<br />
呆在家里，这样你就能接电话了。</p>
</blockquote>
<p>In this context, they've added the <a href="https://resources.allsetlearning.com/chinese/grammar/Change_of_state_with_%22le%22" rel="nofollow noreferrer">change of state 了</a> to refer to a future change of state: it's being said to someone who will change from</p>
<ol>
<li><em>State 1</em>: not being at home and therefore not being able to answer the phone, to</li>
<li><em>State 2</em>: being at home and therefore being able to answer the phone.</li>
</ol>
<p>Dropping the 了 would be appropriate if there were no change of state involved (e.g., the person is already at home).</p>

CC BY-SA 4.0
2020-09-07T10:43:59.897Z
2020-09-07T10:43:59.897Z
Becky 李蓓
<blockquote>
<p>呆在家里， 这样你就能接电话了。</p>
</blockquote>
<p>This dictionary definition addresses the use of 了:</p>
<blockquote>
<p>用在句尾或句中停顿的地方，表示出现某种新情况或发生某种变化（这种新情况可以是已经发生，也可以是即将发生，还可以是一种<strong>假设</strong>）</p>
</blockquote>
<p>Basically, it says: <em>used in the middle or end of the sentence, denoting new circumstances or changes take place(the new circumstance could be something already happened, will happen, or <strong>just a hypothesis</strong>)</em></p>
<p>Your example is a <em><strong>hypothesis</strong></em>.  <em>If you stay home, you would be able to pick up the phone call</em>.</p>
<p>Other examples for the usage: 天要下雨我就不出门了。要是不走我就见到他了。</p>

CC BY-SA 4.0
2020-09-07T23:31:06.110Z
2020-09-07T23:31:06.110Z
dan
<p>Your sentence can be written without 了。</p>
<p>呆在家里，这样你就能接电话。</p>
<p>If it is a translation from English, it is maybe a bit short, it is missing the 'if' clause:</p>
<p>等在家里，如果有人打电话，你就能接到了。</p>
<p>What is 了 doing?</p>
<p>了 有表示过去时，现在进行时，将来时的意思。</p>
<p>In your case, 了 has 将来时的意思。</p>

CC BY-SA 4.0
2020-09-08T01:41:43.387Z
2020-09-08T01:41:43.387Z
Pedroski
<p>The final particle 了 has been discussed in one of my previous post. Let's recap as follows:</p>
<p>The final particle 了 is the trace of an operation whereby the time frame T associated with the speaker/co-speaker (i.e. the hic et nunc) is susceptible of locating a process P, and that T indeed locates/will locate P. In practical terms, the process P is &quot;expected&quot; to happen (&quot;expected&quot; is a bit too strong, but I can't find a better term to make it easy to understand). For example:</p>
<p>1- 她昨天看到姚明。- She happened to see Yao Ming yesterday.<br>
1a - 她昨天看到姚明了。- She finally got to see Yao Ming yesterday.</p>
<p>2 - 我要回家。- I want/need to go home.<br>
2a - 我要回家了。- It is time for me to go home.</p>
<p>In (1a) and (2a), the process is/was expected in one way or another, which is not the case in (1) and (2).</p>
<p>In &quot;呆在家里，这样你就能接电话了&quot;, the process &quot;你接电话&quot; is expected. You are waiting for a phone call, and you are not sure how &quot;you receive the phone call&quot; can happen. I tell you what: you stay at home, then it will happen.</p>

CC BY-SA 4.0
2020-09-08T01:06:49.783Z
2020-09-08T01:06:49.783Z
KK_Tse
<p>In the sentence &quot;呆在家里， 这样你就能接电话了&quot;, I can't see why &quot;了&quot; is used in this sentence.
I study Chinese these days, and I think that I can just say &quot;这样你就能接电话&quot;, but in this example sentence, &quot;了&quot; is used. I know that &quot;了&quot; is often used as the meaning of &quot;completion of action&quot; or &quot;change of action or state&quot;. Could you help me understand the sentence correctly?</p>

<grammar><particles>
What does "了" do in the sentence "呆在家里， 这样你就能接电话了"?
# What does "了" do in the sentence "呆在家里， 这样你就能接电话了"?

(Asked by: username_0 on 2020-09-07)

In the sentence "呆在家里， 这样你就能接电话了", I can't see why "了" is used in this sentence.
I study Chinese these days, and I think that I can just say "这样你就能接电话", but in this example sentence, "了" is used. I know that "了" is often used as the meaning of "completion of action" or "change of action or state". Could you help me understand the sentence correctly?

**Tags:** grammar, particles


---

## 5 answers

### Answer by username_1 on 2020-09-07. Score: 2 | Accepted answer

I will take advantage of this question to write a summary of the **sentence-final 了** or **modal 了**, which occurs at the *end of a sentence*. [Also, the **sentence-final 了** should not be confused with the [**perfective or aspectual 了**](https://chinese.stackexchange.com/a/40507/25265), which occurs just *after a verb* and marks a *bounded action*.]

From Charles N. Li, Sandra A. Thompson - *Mandarin Chinese: A Functional Reference Grammar*, they consider the sentence-final 了 to signal a **Currently Relevant State** (CRS), that is, *了 marks a state of affairs with a current relevance to the particular situation.* Although in the book they argue otherwise, I believe in all cases there is always an inherent *change of state*. We can understand:

* *Currently*: refers to the particular situation (and not necessarily to the present or even real situation). For example:

  > 前一个星期票都卖光**了**。
  >
  > One week ago, all the tickets were sold out ("All the tickets were sold out" is a Currently Relevant State respect to "One week ago").

  > 我是法国人就不会说这么坏的法文**了**。
  >
  > If I were French, then I wouldn't be speaking such bad French ("I wouldn't be speaking such bad French" is a Currently Relevant State respect to "If I were French").
* *Relevance*: the state of affairs given by the sentence is relevant for the speaker and the hearer in the context of the particular situation.
* *State*: refers to the state of affairs signaled by the sentence with 了. It can be classified into the following possibilities:

  1. ("Simple") **change of state**: Previously the state of affair did not hold, but now currently holds (thus, it is relevant). For example:

     > 他知道那个消息**了**。
     >
     > He knows about that piece of news (he did not before).

     > 已经四点**了**。
     >
     > It's already four o'clock (it was not before).

     But also, the change could be about the state of knowledge of the speaker or the hearer. For example:

     > 下雨**了**。
     >
     > It's raining (either it was not raining before or the speaker has just realized it).

     > Q: 她怎么样？A: 她做教授**了**。
     >
     > Q: How is she? A: She has become a professor (the first person did not knew about this state).
  2. **Corrects a wrong assumption**: The current situation contradicts an assumption. For example:

     > [A kid who does not want to eat his/her food, but the same food as the adults. Her mother says:]
     >
     > 一样的**了**。
     >
     > It's the same！(You are wrong in thinking you are eating something different).
  3. **Reports current progress**: the speaker uses 了 to show concern for the progress of an state. For example:

     > [School official registering children:]
     >
     > 你几岁？
     >
     > How old are you?

     > [A relative:]
     >
     > 你几岁**了**？
     >
     > How old are you?
  4. **What happens next**: the current state of affairs is relevant for what can happen on the following.

     > [Someone is arriving:]
     >
     > 他进来了。
     >
     > He is coming in.
  5. **Announces the finality of a statement**: Introduces the statement into the current situation. Otherwise the sentence might sound incomplete, requiring some other justification to make it relevant. For example:

     > [As an answer to why the speaker did not study in a university:]
     >
     > 因为那里学费太贵。
     >
     > Because the tuition fees are too expensive there (the situation was already introduced).

     > [One student complaints to another:]
     >
     > 学费太贵**了**!
     >
     > The tuition fees are really too expensive!


---

### Answer by username_2 on 2020-09-07. Score: 3

Judging from [this webpage](http://www.xuexila.com/english/way/c39349.html), it's a translation from the English:

> Stay home so you can answer the phone.  
> 呆在家里，这样你就能接电话了。

In this context, they've added the [change of state 了](https://resources.allsetlearning.com/chinese/grammar/Change_of_state_with_%22le%22) to refer to a future change of state: it's being said to someone who will change from

1. *State 1*: not being at home and therefore not being able to answer the phone, to
2. *State 2*: being at home and therefore being able to answer the phone.

Dropping the 了 would be appropriate if there were no change of state involved (e.g., the person is already at home).


---

### Answer by username_3 on 2020-09-07. Score: 1

> 呆在家里， 这样你就能接电话了。

This dictionary definition addresses the use of 了:

> 用在句尾或句中停顿的地方，表示出现某种新情况或发生某种变化（这种新情况可以是已经发生，也可以是即将发生，还可以是一种**假设**）

Basically, it says: *used in the middle or end of the sentence, denoting new circumstances or changes take place(the new circumstance could be something already happened, will happen, or **just a hypothesis**)*

Your example is a ***hypothesis***. *If you stay home, you would be able to pick up the phone call*.

Other examples for the usage: 天要下雨我就不出门了。要是不走我就见到他了。


---

### Answer by username_4 on 2020-09-08. Score: 1

Your sentence can be written without 了。

呆在家里，这样你就能接电话。

If it is a translation from English, it is maybe a bit short, it is missing the 'if' clause:

等在家里，如果有人打电话，你就能接到了。

What is 了 doing?

了 有表示过去时，现在进行时，将来时的意思。

In your case, 了 has 将来时的意思。


---

### Answer by username_5 on 2020-09-08. Score: 0

The final particle 了 has been discussed in one of my previous post. Let's recap as follows:

The final particle 了 is the trace of an operation whereby the time frame T associated with the speaker/co-speaker (i.e. the hic et nunc) is susceptible of locating a process P, and that T indeed locates/will locate P. In practical terms, the process P is "expected" to happen ("expected" is a bit too strong, but I can't find a better term to make it easy to understand). For example:

1- 她昨天看到姚明。- She happened to see Yao Ming yesterday.  
1a - 她昨天看到姚明了。- She finally got to see Yao Ming yesterday.

2 - 我要回家。- I want/need to go home.  
2a - 我要回家了。- It is time for me to go home.

In (1a) and (2a), the process is/was expected in one way or another, which is not the case in (1) and (2).

In "呆在家里，这样你就能接电话了", the process "你接电话" is expected. You are waiting for a phone call, and you are not sure how "you receive the phone call" can happen. I tell you what: you stay at home, then it will happen.


---

