/wɪtʃ; [US] hwɪtʃ; hwɪtʃ/
interrog det (used to ask sb to specify one or more people or things from a limited number 用以要求某人在有限数量中指明某人或某事物)
*Which way is quicker by bus or by train? 怎么去更快--坐公共汽车还是坐火车?
* Which Mr Smith do you mean the one who teaches history or the one who teaches music? 你说的是哪个史密司先生--是教历史的那个还是教音乐的?
* Which languages did you study at school? 你上学时学的都是哪些语言?
* Ask him which platform the London train leaves from. 问问他到伦敦去的列车从哪个站台开出? Cf 参看 what1. =>Usage 见所附用法.

interrog pron which person or thing (from a limited number) （有限数量中的）哪个人或哪个事物
*Which is your favourite subject? 你最喜欢哪个科目?
* Which of the boys is tallest? 这些男孩儿哪个最高?
* Here are the chairs. Tell me which are worth buying. 就是这些椅子. 告诉我买哪几把好.
* The twins are so much alike that I can't tell which is which, ie can't distinguish one from the other. 这对双胞胎长得可真像, 我都分不出谁是谁了.

rel det 关系限定词 (fml 文) (used to refer back to the preceding n or statement 用以复指前文的名词或内容)
*The questions were all on opera, about which subject I know nothing. 那些问题都是关于歌剧的, 我对歌剧一无所知.
* The postman comes at 6.30 in the morning, at which time (ie when) I am usually fast asleep. 邮递员早晨6点30分来, 这个时候我通常还睡着大觉呢.

rel pron 关系代词 (used to refer to sth previously mentioned 用以指提到过的事物)
*Take the book which is lying on the table. 把桌子上的那本书拿走.
* A house which overlooks the park will cost more. 面向公园的房子贵些.
* Read the passage to which I referred in my talk. 读一读我在讲话中提到的那段文章.
* His best film, which won several awards, was about the life of Gandhi. 他的最佳影片, 就是荣获几项奖的那部, 是关于甘地生平的.
* His new car, for which he paid 7000, has already had to be repaired. 他那辆新汽车, 花了7000英镑买的, 已经得修理去了.

NOTE ON USAGE 用法
*Compare the use of which and what as determiners and pronouns in questions. 试比较which和what用作限定词和代词时, 在疑问句中的用法. Which refers to one or more members of a limited group *which指在有限数量中的一个或一些
*Which car is yours/Which is your car? The Ford or the Volvo? 哪辆汽车是你的[哪辆是你的汽车]? 是｀福特＇牌的还是｀富豪＇牌的? What is used when the group is not so limited 若所指的并非在有限的数量中, 要用what
*What are your favourite books? 你最喜欢什么书? When we are referring to people, we often use which even if the choice is not restricted 指人时, 即使所在范围不受限制, 也往往用which
*Which/What actors do you admire most? 你最喜爱哪些演员?

determiner, pron
[Language: Old English;Origin: hwilc]
used to ask or talk about one or more members of a group of people or things, when you are uncertain about it or about them
　Which book are you looking for?
　Which are the most important crops?
　Miranda was sure it was one of them, but was not sure which.
which of
　I don't know which of us was the more scared.
used after a noun to show what thing or things you mean
　Did you see the letter which came today?
　Now they were driving by the houses which Andy had described.
used, after a comma in writing, to add more information about the thing, situation, or event you have just mentioned
　The house, which was completed in 1856, was famous for its huge marble staircase.
　One of the boys kept laughing, which annoyed Jane intensely.
　He was educated at the local grammar school, after which he went on to Cambridge.
　She may have missed the train, in which case (=if this happens) she won't arrive for another hour.
don't know/can't tell etc which is which
if you do not know which is which, you cannot see the difference between two very similar people or things
　The twins are so alike I can never tell which is which.

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HINT sense 2
In informal and spoken English, it is more usual to use that : This is the one that I wanted.

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