About usage of "了“
How can I tell the differences between below three sentences in Chinese.
1.I learnt Chinese for 3 years in Shanghai.
2.I have been learning Chinese for 3 years in Shanghai.
(I am still in Shanghai and learning until now)
3.I have learnt Chinese in Shanghai.

The reason is all about the usage of "了“. It‘s always eating me.
Here are my own answers, please help me out:)

1.我在上海学了3年汉文
2.我在上海学了3年汉文了
3.我在上海学过汉文还是我在上海学汉文了

Question

About usage of "了“
How can I tell the differences between below three sentences in Chinese.
1.I learnt Chinese for 3 years in Shanghai.
2.I have been learning Chinese for 3 years in Shanghai.
(I am still in Shanghai and learning until now)
3.I have learnt Chinese in Shanghai.

The reason is all about the usage of "了“. It‘s always eating me. 
Here are my own answers, please help me out:)

1.我在上海学了3年汉文
2.我在上海学了3年汉文了
3.我在上海学过汉文 还是 我在上海学汉文了

Answer

1.我在上海学过3年中文（这里不用“了”，而用“过”，描述过去发生过的动作）

2.我已经在上海学了3年中文了（have been doing sth描述从过去持续到现在发生的事件或动作，表示从3年前就开始在上海学中文，这个动作一直持续到现在）

3.我曾经在上海学过中文（have learnt是描述过去曾经发生的事情，用“曾经学过”来翻译比较合适，只描述过去发生过的事件或动作，不确定现在是否还在学）

Answer

HI, Tony.I'm Anna .haha,,,,like you helped me several months ago,as a chinese ,I can help you with these questions.
1.我在上海学了三年的汉语。（只是一般的过去式，陈述性的）
2.我（一直）在上海学汉语已经三年了。（这里是含有还在学的意思的）
3.我已经在上海学了三年的汉语。（强调已经学过）

呵呵，“了”在中文里只是音节助词，也可表示一句话的结尾词，所以一般可用可不用。而分清楚说话人本人的意思则要靠另外加的词，如“一直”、“已经”and so on.
So ,now that you can type chinese fruently ,I believe in you that you can tell them.
FIGHTING!!!!

Answer

in my opinion,hardly have the meaning of tense of perfect expressed when 了 appears

Answer

wow~jiabao is so great

Answer

1.我过去在上海学过三年汉语
2.我在上海学了三年汉语了（现在还在学）
3.我在上海学了三年汉语（现在可能还在学）