Chinese-all-day-breakfast/MD/g1-48.md

Use of the modal particle 了

Basic concept

The modal particle 了 is placed at the end of a sentence to indicate that the event referred to took place in the past. The difference between 了 as modal particle and 了 to indicate perfect aspect is that the latter only shows the completion of the verb, whereas the former shows the completion of the whole sentence or event, implying some change of situation.

他買了書了。

The first 了 in the sentence above indicates only the completion of the action of 買書, whereas the second 了 marks some change of situation on the part of 他 as a result of the completion of the book-buying process: originally he did not have the book, but now he has.

Basic patterns

(Please compare against the patterns for the perfect aspect in the previous section.)

1. Affirmative sentence

   Subject + verb (+ object) + 了
   e.g. 他們看足球賽了。
   

2. Negative sentence (note 了 is dropped here)

   Subject + 沒 (有) + verb (+ object)
   e.g. 他們沒看足球賽。
   

3. Interrogative sentence

   Subject + verb + object + 了沒有﹖
   or Subject + verb + object + 了嗎﹖
   or Subject + verb + 沒 + verb + object﹖ (here the verb is
   usually monosyllabic)
   e.g. 他們看足球賽了沒有﹖
   他們看足球賽了嗎﹖
   他們看沒看足球賽﹖
   

   Notes

4. As is obvious, when there is no object, one cannot tell the perfect aspect 了 from the modal particle 了. In such a case, 了 can be regarded as fulfilling both functions:

   她來了。 我們懂了。
   

5. A simple statement about events that happened in the past does not require a 了 at the end of the sentence:

   我昨天下午看足球賽﹐晚上沒出去。