Change of state with 了
了 gets called a lot of things. It’s a pretty tricky concept for foreigners to wrap their heads around, especially if they’re thinking of it in terms of “time” or “tense.”
了 is a change of state marker. If something goes from being a certain way to another way, you express that concept with 了.
我六月初会去台湾. |
I’m going to Taiwan in early June. |
我明白了. |
I understand now (I didn’t before). |
孔子来了. |
Confucius is coming. |
In the second example, Confucius was previously somewhere else, not intending to come over. Now that he’s in the process of coming over, we mark that change with 了.
了 is used quite frequently to express a completed action or a past action, but you should never get in the habit of “translating” past tense with 了.
That’s because it also marks completed actions, particularly when you have simple subject-verb-object sentences.