“”.
(English only)
Both serve as the negation form of Chinese characters. However, the meanings differ a lot.
“不” means a refusal to do something, or saying more directly, “不”means the speaker do not want to do the thing it negates, and, since it is a question about intention, speaker could use “不” to negate a action in past, present, and future all.
Instead“沒” is just stating a fact that the speaker did not do in the past. It is not related to speaker’s intention about doing something. Because it is just stating a fact, it would always be used to refer to the past.
For example, if you ask a friend whether he has watched “Doctor Strange” or not, the answer “我不看這個電影” means “I don’t want to watch this movie” and “我沒看這個電影” only means “I haven’t watched this movie”(or, to convey this meaning in a more natural way for us, “我還沒看這個電影”).
Some exceptions also need to be noted here:
1. "沒能” and “不能”. “我不能” means the speaker shouldn’t or do not have the ability to do something, whereas “我沒能” means speaker did not do something, although he/she had the intention or obligation to do this.
For example “我不能喝咖啡” means “I shouldn’t drink coffee”, and“我沒能喝咖啡”means “I did not drink coffee(although I wanted to)”.
2. “我沒有” means the speaker do not possess something. There is not a negation form called“不有”, only “沒有”.