- （与前面的动词连用时亦作n't）used with an auxiliary verb or 'be' to form the negative［与助动词或be构成否定式］不：
he would not say
他不愿说
she isn't there
她不在那儿
didn't you tell me?
你没告诉我吗？
- used in some constructions with other verbs与其他动词一起用于某些结构中不：
with infinitive he has been warned not to touch他已被告诫不得触摸
the pain of not knowing
不知道的痛苦
she not only wrote the text but also researched the photographs.
她不仅写了文章而且仔细研究了照片。
- used as a short substitute for a negative clause用于替代否定从句不, 没有：
maybe I'll regret it, but I hope not
也许我会后悔, 但我希望不会
'Don't you keep in touch?' 'I'm afraid not.'
“你们互相不联系吗？”“恐怕是这样。”
they wouldn't know if I was telling the truth or not.
他们不会知道我是否在说实话。
- used to express the negative of other words用于否定其他词不, 没有：
not a single attempt was made
连一次都没有试过
treating the symptoms and not the cause
治标不治本
'How was it?' 'Not so bad.'
“情况如何？”“不算太糟。”
- used with a quantifier to exclude a person or part of a group与量词连用以排除全部中的一部分不是：
not all the poems are serious.
并非所有的诗都是严肃的。
- less than (used to indicate a surprisingly small quantity)少于（用于表示数量惊人地小）：
the brakes went on not ten feet from him.
在离他连10英尺都不到的地方车才刹住。
- used in understatements to suggest that the opposite of a following word or phrase is true用于保守的陈述不算; 不到：
the not too distant future
不太远的将来
not a million miles away.
不到100万英里以外。
- informal, humorous following and emphatically negating a statement〈非正式, 幽默〉不, 恰恰相反：
that sounds like quality entertainment - not.
那听上去像高档娱乐——不, 恰恰相反。
ORIGIN: a usage popularized by the film Wayne's World.
- Electronics a Boolean operator with only one variable that has the value one when the variable is zero and vice versa【电子】非。
- （亦作not gate）a circuit which produces an output signal only when there is not a signal on its input“非”电路。
not at all
- used as a polite response to thanks（对致谢者的应答语）别客气, 不用谢。
- definitely not肯定不, 完全不：
'You don't mind?' 'Not at all.'
“你不介意吗？”“一点儿也不。”
not but what
- archaic nevertheless〈古〉然而, 不过：
not but what the picture has its darker side.
不过画面也有它较为黑暗的一面。
not half
- 见HALF.
not least
- 见LEAST.
not quite
- 见QUITE.
not that
- it is not to be inferred that不能据此认为…, 并不是…：
I'll never be allowed back-not that I'd want to go back.
我永远不会被允许回去了——并不是我想要回去。
not a thing
- nothing at all什么也没有。
not very
- 见VERY.