<p>There seems to be a cultural difference in usage here. ‘之前知道’ means you learned this before and still know it. 'I knew' often means 'I've forgotten', unless qualified like below.</p>

<p>A：That girl married that boy.
A:这个女孩和那个男孩结婚了。</p>

<p>B could answer:<br>
B：I know.
B:我知道的。<br>
    or<br>
B：I already know/knew that.
B：我之前就知道了。 </p>

<p>A：Who did that girl marry?
A:她和谁结婚了？<br>
B：I knew, but I can't remember now.
B:我知道是谁，但是我忘了。</p>

CC BY-SA 3.0
2017-06-17T00:11:56.983Z
You have translated the English, but that is not a typical Chinese answer. Would you really say that? I think you would just say '我忘了。‘
Pedroski
CC BY-SA 3.0
2017-06-14T22:47:57.747Z
2017-06-16T17:06:08.527Z
2017-06-16T17:06:08.527Z
Pedroski
<p>The single sentence "I knew it before" isn't related to whether "I did it (after know)".<br>If there is any relationship, it dues to the context.</p>

<ul>
<li>A: Shanghai Disney resort has been opened, had you been there?<br />
上海迪士尼已经开业了，你去过那里吗？<br>
B: I knew it before, but I have not been there.<br />
我之前就知道了，但我没去过。</li>
<li>A: Do you know that typhoon is coming?<br />
你知道台风要来了吗？<br />
B: I <strong>already</strong> knew it yesterday. (I knew it early than you think)<br />
我昨天<strong>就</strong>知道了/我昨天<strong>已经</strong>知道了/我昨天<strong>就已经</strong>知道了。</li>
<li>A: Did you know that Olympic Games is about to close?<br />
你知道奥运会要结束了吗？<br />
B: I <strong>just</strong> knew it yesterday. (I knew it later than you think)<br />
我昨天<strong>才</strong>知道。</li>
</ul>

CC BY-SA 3.0
2017-06-14T22:13:26.397Z
Jacky, don't say 'I knew it', say 'I know'. I have a friend who always does that. I always tell her to say 'I know', but she keeps saying 'I knew it'.  'I knew it' means 'I have forgotten'. For 'I knew it before' say 'I've heard about it before' :)
Pedroski
CC BY-SA 3.0
2017-06-15T00:25:50.397Z
@Pedroski Thanks, this is exactly the distinction that I am enquiring about in Chinese - specifically, whether such a distinction exists. Do you think it does?
Somniare
CC BY-SA 3.0
2017-06-15T02:14:50.417Z
After leaving school for years my English level is worse than before...
xenophōn
CC BY-SA 3.0
2017-06-15T21:59:06.173Z
@Somniare No such distinction in Chinese, say '我忘了‘ when 'I knew' carries the meaning 'I've forgotten'. Jacky, your English is much better than my Chinese!
Pedroski
CC BY-SA 3.0
2017-06-14T13:05:27.260Z
2017-06-14T13:12:47.057Z
2017-06-14T13:12:47.057Z
xenophōn
<p>The only thing you need to remember is that "了" is very similar to "already," which explains the context of "之前知道了" that you knew something and you likely still know it.</p>

CC BY-SA 3.0
2017-06-17T17:11:34.133Z
2017-06-17T17:11:34.133Z
Ethan Chen
<p>If someone said '我之前知道【proposition】' would this imply that they knew it before, but no longer do? How about '我之前知道了【proposition】'?</p>

<p>What about when the time is specific such as ‘昨天我知道【proposition】’? Would this imply that I no longer know the proposition?</p>

<p>Thanks in advance.</p>

CC BY-SA 3.0
2017-06-14T12:52:11.223Z
this seems to have already been answered by previous Q:https://chinese.stackexchange.com/questions/24109/can-one-use-%e8%bf%87-in-conjunction-with-%e7%9f%a5%e9%81%93

我之前知道 "knew it (already, even) before (earlier)"
知道了＂learned it＂（passed from a state of not knowing to knowing)
user6065
CC BY-SA 3.0
2017-06-14T17:39:01.430Z
This is a difficult question to clarify in a few sentences.
mootmoot
CC BY-SA 3.0
2017-06-14T23:02:50.890Z
‘我昨天就知道了’ = 'I heard/learned about it yesterday.'
Pedroski
<grammar><meaning><word-choice>
What would the meaning of '之前知道' be? And '之前知道了'?
# What would the meaning of '之前知道' be? And '之前知道了'?

(Asked by: username_0 on 2017-06-14)

If someone said '我之前知道【proposition】' would this imply that they knew it before, but no longer do? How about '我之前知道了【proposition】'?

What about when the time is specific such as ‘昨天我知道【proposition】’? Would this imply that I no longer know the proposition?

Thanks in advance.

**Tags:** grammar, meaning, word-choice

> **Comments:**
> **username_1**: this seems to have already been answered by previous Q:https://chinese.stackexchange.com/questions/24109/can-one-use-%e8%bf%87-in-conjunction-with-%e7%9f%a5%e9%81%93  我之前知道 "knew it (already, even) before (earlier)" 知道了＂learned it＂（passed from a state of not knowing to knowing)  
> **username_2**: This is a difficult question to clarify in a few sentences.  
> **username_3**: ‘我昨天就知道了’ = 'I heard/learned about it yesterday.'  

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## 3 answers

### Answer by username_3 on 2017-06-14. Score: 2 | Accepted answer

There seems to be a cultural difference in usage here. ‘之前知道’ means you learned this before and still know it. 'I knew' often means 'I've forgotten', unless qualified like below.

A：That girl married that boy.
A:这个女孩和那个男孩结婚了。

B could answer:  
B：I know.
B:我知道的。  
or  
B：I already know/knew that.
B：我之前就知道了。

A：Who did that girl marry?
A:她和谁结婚了？  
B：I knew, but I can't remember now.
B:我知道是谁，但是我忘了。

> **Comments:**
> **username_3**: You have translated the English, but that is not a typical Chinese answer. Would you really say that? I think you would just say '我忘了。‘  

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### Answer by username_4 on 2017-06-14. Score: 1

The single sentence "I knew it before" isn't related to whether "I did it (after know)".  
If there is any relationship, it dues to the context.

* A: Shanghai Disney resort has been opened, had you been there?  
  上海迪士尼已经开业了，你去过那里吗？  
  B: I knew it before, but I have not been there.  
  我之前就知道了，但我没去过。
* A: Do you know that typhoon is coming?  
  你知道台风要来了吗？  
  B: I **already** knew it yesterday. (I knew it early than you think)  
  我昨天**就**知道了/我昨天**已经**知道了/我昨天**就已经**知道了。
* A: Did you know that Olympic Games is about to close?  
  你知道奥运会要结束了吗？  
  B: I **just** knew it yesterday. (I knew it later than you think)  
  我昨天**才**知道。

> **Comments:**
> **username_3**: Jacky, don't say 'I knew it', say 'I know'. I have a friend who always does that. I always tell her to say 'I know', but she keeps saying 'I knew it'.  'I knew it' means 'I have forgotten'. For 'I knew it before' say 'I've heard about it before' :)  
> **username_0**: @username_3 Thanks, this is exactly the distinction that I am enquiring about in Chinese - specifically, whether such a distinction exists. Do you think it does?  
> **username_4**: After leaving school for years my English level is worse than before...  
> **username_3**: @username_0 No such distinction in Chinese, say '我忘了‘ when 'I knew' carries the meaning 'I've forgotten'. Jacky, your English is much better than my Chinese!  

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### Answer by username_5 on 2017-06-17. Score: 0

The only thing you need to remember is that "了" is very similar to "already," which explains the context of "之前知道了" that you knew something and you likely still know it.


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