Modal particle le 了(or sentence-end le 了)

1. Le le 了 used to affirm the completion of the action and to make a point about the present situation
2. Le le 了 used to ask or answer questions about whether someone has done something. (Did you ...? or Have you ...?)
3. Le le 了 used to ask about what someone did
4. Le le 了 used to ask or answer questions about where someone went/has gone
5. Le le 了 used to ask or answer general questions about who did something without requesting specific information about quantity, duration and so on
6. Asking and answering questions about how long someone has not done something
7. Special verbs taking a phrase of duration.
8. Modal particle le used to sum up after a series of actions