没 + V / 没 + V过 / 还没…呢【méi / méi…guo / hái méi…ne】

没 negates an event, and it changes the aspect markers around it. 了 after the verb drops; 过 stays.

了 marks that the event took place and 没 says it didn't, so the two can't share a verb. 过 marks experience, and 没…过 is "have never".

• × 我没吃了 → 我没吃
• × 我没去北京过 → 我没去过北京

Not yet: 还没…呢

还没 + verb + 呢 says something hasn't happened yet but is expected to. It is the usual answer to a question with 了.

The question sets the shape of the answer: 你吃了吗 gets 没吃 or 还没呢; 你吃过吗 gets 没吃过.

了 comes back with a length of time

A length of time before 没 + verb, with 了 at the end of the sentence, says how long the not-doing has gone on. This 了 is the sentence-final one: the state still holds.

不…了 is about now

不 + verb + 了 says something has stopped or a plan has changed. 没 reports an event that didn't happen.

Complements stay

A result complement stays after 没 – 没写完, 没听懂, 没找到. Only 了 goes.

• × 我没找到了 → 我没找到