1.用作名词,表示“足够（的数目或数量）,没有复数形式,但根据情况可表示复数意义.如：
Enough has been said of this problem.有关这个问题,已经谈得够多了.
Enough were present to constitute a quorum.出席的人数够法定人数.
2.用作形容词,通常修饰复数名词或不可数名词,可放在被修饰名词之前或之后（但以前置为多见）.如：
He has enough money to buy a car.他有足够的钱买辆汽车.
We have time enough to get to the airport.我们来得及赶到机场.
有时与某些具有形容词意味的名词连用,此时 enough 必须后置,且该名词通常不用冠词.如：
I was fool [=foolish] enough to accept his offer.我接受他的提议真是太傻了.
3.用作副词,可用来修饰形容词、副词、动词等,此时总是放在被修饰语之后.如：
You don’t relax enough.你休息不足.
I wonder if it’s large enough.我不知道它是否够大.
You’re not driving fast enough.你开车开得不够快.
修饰形容词时要后置,即使被修饰的形容词后面修饰有名词也是如此.如：
We haven’t got a big enough house.我们的房子不够大.
He was a handsome enough child.他是一个非常帅气的孩子.
但是,如果enough修饰整个名词词组,则置于形容词之前.比较：
We haven’t got big enough nails.我们没有够大的钉子.
We haven’t got enough big nails.我们没有足够多的大钉子.
4.可用于某些副词之后对一情景进行评论.可以这样使用的词有curiously,funnily,interestingly,oddly,strangely,surprisingly等.如：
Strangely enough,I won first prize.说来奇怪,我得了一等奖.
Curiously enough,he seemed to know that already.说也奇怪,他似乎已经知道这事了.
Interestingly enough,this proportion has not increased.说也有趣,这个比例并未增加.
Oddly enough,we didn’t meet,although we were both there.真怪,我们没有碰面,虽然我们都在那里.
5.在通常情况下,enough不能用作表语,除非其主语是代词或是那些具有（或暗示有）数量意义的名词.如：
One such dictionary is enough.这样的词典一本就够了.
Five men will be quite enough.5个人完全够了.
I did all I could,but it wasn’t enough.我做了我能做的一切,但是还不够.
比较下面的正误句子：
误：The beer isn’t enough.啤酒不够.
正：There isn’t enough beer.啤酒不够.
误：Was the time enough?时间够吗?
正：Did you have enough time?你们时间够吗?
6.用于cannot...enough,表示“无论怎样……都不够”.如：
I cannot thank you enough.
You cannot be careful enough.你越仔细越好.
I cannot say enough in praise of his work.我对他的工作赞扬不已,怎么说也不嫌过分.
摘自“中学英语高频词详解词典”的enough词典.
希望对你有用