The particle 了
The word 了 le is a word with many roles. As a tense particle, we locate it after the verbs to indicate a completed action, it is similar to the present perfect tense, well…yeah, without changing the forms of the verbs of course. “I have eaten” is simply “我吃饭了 Wǒ chīfàn le”. 了 can also function as modal particle to indicate certain tone. We will get to that later.
One thing to mention here is that 了 is not always required in the past tense. I have seen students trying to squeeze it in just to get it grammatically correct. To express some actions in the past, we can see an example that doesn’t involve 了：
|我 上 个 星期 去 海边 散步。|
Wǒ shàng gè xīngqī qù hǎibiān sànbù.
Last week i went to the beach to take a walk.
When we talk about past actions, if there is a time indicator, such as 昨天 zuótiān (yesterday), 上个星期 shàng gè xīngqī（last week) ,去年 qùnián (last year), and also a location, and you want to people to focus on where you went, when you went, not whether you went, adding 了 here would be excessive and sounds very unnatural.
|我 昨天 去 超市 （了）。|
Wǒ zuótiān qù chāoshì （le）.
Yesterday i went to the supermarket.
In this sentence, adding 了 or not will both be OK, because the time was already set in the past, so people won´t have confusion, meanwhile the sentence is quite short, so adding 了 is good too, since it won´t make it lengthy and out of focus.
|晚上 我 做 了 西红柿 炒 鸡蛋。|
Wǎnshàng wǒ zuò le xīhóngshì chǎo jīdàn.
At night i made a dish with tomato and eggs.
In this sentence , adding 了 is necessary, without it people wonder whether you have made the dish yet.
Ok now we go back to how we should really use 了, for example:
|今天 早上 我 跑步 了。|
Jīntiān zǎoshàng wǒ pǎobù le.
This morning i went to run.
今天 早上 你 跑步 了 吗？
Jīntiān zǎoshàng nǐ pǎobù le ma ？
Did you run this morning?
Now we have to be careful with the answers.
Wǒ pǎo(bù )le.
Yes, i ran.
wǒ méi pǎo(bù).
No, i didn´t run.
There are two things to look out for here. ① In the negative answer we use 没有méiyǒu instead of 不bù(of course you can use 没méi too)，but remember the 了 has to be taken out. ② Since 跑步pǎobù is what we call separable verbs(also called clutch verbs, it is when the verbs can be taken apart and function as independent words, like 跑pǎo is a word too, and also these words also keep a loose V+O structure), so we can answer with only the first part of the whole word, hence “我跑了wǒ pǎo le/我没跑wǒ méi pǎo”. We use this way of answering far more frequently than the complete answer.
How to better understand the word 了
The role of the word 了 is quite unpredictable. It can be used for the past but also in the future. It can also function as modal particle to express excessiveness 太…了tài …le , also to emphasize on the affirmative tone 要…了yào …le. What does it do actually?
I would say as a tense particle, it determines the completion of an action, either it is in the past or in the future, for example:
|我 吃 了 饭 就 去 找 你。|
wǒ chī le fàn jiù qù zhǎo nǐ.
I will look for you once i am done with my meal.
This sentence aims at locating the orders of two actions, the second action ( looking for the person) happens after completing the first action (eating). And the structure is 了…就… , don´t forget we need both words to make it function.
Let´s savour a bit of that and see some more examples:
|现在 太 晚 了。|
Xiànzài tài wǎn le.
太…了tài …le is a very common expression, here 太晚了 tài wǎn le has a negative connotation, but the structure can work for both positive and negative situations.
|我 要 回 家 了。|
wǒ yào huí jiā le.
I need to go home right now.
你 别/不 要 生气 了。
Nǐ bié/bú yào shēngqì le.
Don´t be angry.
要…了(need to do something right away) and 别/不要…了(don´t) both emphasize on the affirmative/negative tone, like “I am going to do…right now” or “stop doing…now!”
There are other phrases like this, it can be confusing sometimes, but most important of all, try to practice often and never detach yourself from the context, that is the best way to learn it. Good luck and I hope you enjoyed this article 🙂