The most commonly used negator is bu4不 and only bu4不 can be used when it is used to negate a habitual situation, an ongoing situation, an intention or a future event, for instances:
(Negation of a future event) 我不一定來。
(Negation of an intention) 我不能來。
(Negation of an ongoing situation) 他不在图书馆看书，他在那里工作。
(Negation of a habitual situation) 他在家不看书，只看电视。
The negator mei2(you3)沒(有) must be used to negate a completed event, for example:
他昨天沒来。(He did not come yesterday.)
The negator bie2別 is primarily used in unrealized situations, for instances:
(Negation of a command) 你别听收音机！
(Negation of a request) 请你别说话？
Reference
Sun, Chaofen (2006). Chinese: A linguistic introduction. Univ of California Press. Cambridge: Cambridge University Press.
