1. 了(le) - Completion of an action When placed after a verb, the particle 了 indicates the action has been completed.
2. 了(le) - With 快/要/就 When used with 快/要/就, 了 indicates that an event is going to happen very soon. 快/要/就 are considered interchangeable.
3. 了(le) - In the imperative sentence As a modal particle, 了 can be placed at the end of an imperative sentence to indicate a change of situation. 好了 could mean enough/stop/no more and also used to show one's impatience.
4. 了(le) - When placed at the end of a sentence, 了 could express exclamation.
5. 了(le) - 了 can be used in the passive sentences.
6. 了(le) - 完了 了 can be placed after 完 (wán) to indicate that an action is over. On its own, 完 (wán) means "to finish" or "to complete.
7. 了(le) - Questions The modal particle 了 can be used at the end of a sentence to ask a question.
8. 了(le) - End with 了吗? can be used with 吗 to ask a question.
9. 了(le) - 了+没有 没有 can be used at the end of a sentence to express uncertainty state.
10. 了(le) - 了(perfective aspect particle)-了(modal particle) The perfective aspect particle 了 can follow a verb to indicate completion;a modal particle 了 can be placed at the end of a sentence to indicate 'already'.
11. 了(le) - Past actions and states When placed after a verb, together with an adverb of past time, 了 can describe a past action or state.
12. 了(le) - Continuation from past to present To indicate Continuation of action from past to present.
13. 了(le) - Completion in the past When placed after a verb, together with an adverb of past time, 了 could describe the completion in the past.
14. 了 - 极了(le) extremely / 不得了(liǎo) extremely.
15. 了(liǎo) - When follow a verb with 不, 了 could mean an impossible situation.
16. 了(liǎo) - When placed after a verb with“得”, 了 indicates possibility or finality.
17. 了(liǎo) - 了 can be used as the verb complement in 得了-不了 expression.
