both 与not连用,表示不完全否定,意思是事实上我不全都喜欢这两个,也就是喜欢一个,不喜欢另一个.
而either 用在否定句中,“(两者之中)任何一个 ”,意思是事实上这两个中的任何一个我都不喜欢.
例如
Either of the plans is equally dangerous.
这两个计划中,哪一个都同样有危险.
The news did not shock either of them.
这消息没有使他们任何一个人震惊.
I don't think either of them are at home.
我想他们中任何一个都不在家.
I have bought two books,you can have either.
我买了两本书,你要哪一本都可以.”