- asking for information specifying one or more people or things from a definite set哪一个; 哪一些：
as pronoun which are the best varieties of grapes for long keeping?哪些葡萄品种最宜长期保存？
which of the suspects murdered him?
嫌疑犯中哪一个谋杀了他？
as determiner which way is the wind blowing?风是往哪个方向刮的？
- used referring to something previously mentioned when introducing a clause giving further information那一个; 那一些（用于引导定语从句）：
as pronoun a conference in Vienna which ended on Friday星期五在维也纳闭幕的会议
after prep. it was a crisis for which he was totally unprepared这是一场令他猝不及防的危机
as determiner, after prep. your claim ought to succeed, in which case the damages will be substantial.你的索赔应该会成功, 如果是这样, 赔偿金额会很大。
USAGE
On the differences between which and that in relative clauses， see usage at THAT.
短语
which is which
- used when two or more people or things are difficult to distinguish from each other哪一个是哪一个; 什么是什么：
there is no confusion as to which is which.
哪个是哪个, 不会混淆。
词源