both, either, neither属于不定代词,它们的适用范围都是限于两者之间。

(1)both指”两者都”, 是对两者的肯定,修饰复数名词,如:

Both his father and mother are here. 他们的父母都在这儿.

Both of them are good teachers. 他们两个都是好老师.

They both skate well. 他们两个都很会滑冰.

The children were both too young. 这两个孩子都很年轻.

My parents have both been invited. 我的父母都被邀请了.

(2)either表示”两者中任何一个”, 可以指代或修饰单数名词,做主语时,谓语动词用单数形式,还可以和or搭配,如:

Either book is OK. teacheray.com 两本书都可以.

There is a path on either side of the road. 路的两边各有一条小道.

(3)neither表示”两者都不”,是对两者的否定,反义词是both, neither可以和nor搭配.如:

Neither answer is right. 两个答案都不对.

Neither of my parents has ever read the book. 我父母都没读过这本书.

需要注意的是: either…or…(要么…要么…),neither…nor…(既不…也不…)结构做主语时,谓语动词要与or或nor后面的成分在人称和数上保持一致,也就是我们常说的主谓一致就近原则.如:

Either you or I am right. = Either I or you are right. 要么我对,要么你对.

Neither he nor we have been to NY. = Neither we nor he has been to NY. 他和我们都没去过纽约.