The Difference Between "不" and "没"

How do we say "not-" correctly in Chinese?

Both "不"(bù) and "没"(méi) mean "no, not" in Chinese, but could they be applied in the same situations? This could be very confusing not only for beginners but also for advanced learners. 

The first thing you need to keep in mind is that only "不"(bù) is used to negate adjectives. Adjectives are the kind of words that you use to describe things or persons, like "忙"(máng,  busy), "帅"(shuài, handsome), "高兴" (gāoxìng, happy). So "not busy" "not handsome" "unhappy" would be "不忙"(bù máng) "不帅"(bú shuài) "不高兴"(bù gāoxìng).

When it comes to verbs, "不"(bù) and "没"(méi) are used in different tenses.  Verbs are words of actions, such as "去"(qù, to go), "吃"(chī ,to eat) "说"(shuō, to speak). "不"(bù) is used for present and future, sometimes indicates about unwillingness;  and "没"(méi) is used for past actions. Therefore, "不去" (bú )means "I won't go" or "I am not willing to go", "没去"(méi qù) means "I didn't go".

However, there's one exception, which is the verb "有" (yǒu, to have), the negative form for it is always "没有"(méi yǒu).