英文中which的用法

pron.哪一个；哪一些；哪个；那，指前面提到的事物
adj.哪一个；哪一些
1.QUEST（用于疑问句中）哪个，哪些You use which in questions when there are two or more possible answers or alternatives.Which do they want me to do? declare war or surrender?...他们想让我做什么，宣战还是投降？Which are the ones you really like?...哪些是你们真正喜欢的？'You go down that passageway over there.' — 'Which one?'...“你沿着那条过道走过去。”——“哪条过道？”Which vitamin supplements are good value?哪种维生素补充片好？
2.DET（用于指明在两个或多个答案或选项中所作出的选择）哪个，哪些You use which to refer to a choice between two or more possible answers or alternatives.I wanted to know which school it was you went to...我想知道你上的是哪所学校。I can't remember which teachers I had...我记不清哪些老师教过我。Scientists have long wondered which parts of the brain are involved in musical tasks.科学家们一直想知道大脑的哪些部分是用来处理音乐的。Which is also a conjunction.In her panic she couldn't remember which was Mr Grainger's cabin...在慌乱中她记不清哪个是格兰杰先生的船舱。There are so many diets on the market, how do you know which to choose?市场上有如此多的食物，你怎么知道该选哪些呢？
3.PRON-REL（用于关系从句句首，具体说明所谈论的事物或提供关于它的更多信息）You use which at the beginning of a relative clause when specifying the thing that you are talking about or when giving more information about it.Soldiers opened fire on a car which failed to stop at an army checkpoint...士兵向那辆拒绝在军事检查站停车检查的汽车开了火。He's based in Banja Luka, which is the largest city in northern Bosnia...他驻扎在波斯尼亚北部的最大城市巴尼亚卢卡。Colic describes a whole variety of conditions in which a horse suffers abdominal pain...绞痛包括引起马匹腹部疼痛的各种病症。I'm no longer allowed to smoke in any room which he currently occupies.我不再被允许在他所在的任何一间屋子里吸烟。
4.PRON-REL（用来回指前面句子表达的观点或状况）这，那You use which to refer back to an idea or situation expressed in a previous sentence or sentences, especially when you want to give your opinion about it.They ran out of drink. Which actually didn't bother me because I wasn't drinking...他们把酒喝完了。但实际上这对我来说无所谓，因为我不喝酒。Since we started in September we have raised fifty thousand pounds, which is pretty good going...我们自从9月份开始以来，已经募集到5万英镑，进展相当顺利。Visited Park West. Viewed a flat, no. 76. Which I like.去了中央公园西路，看了一套公寓，76号，我很喜欢。Which is also a determiner.The chances are you haven't fully decided what you want from your career at the moment, in which case you're definitely not cut out to be a boss yet!你此刻很可能尚未完全确立自己的职业目标，在这样的情况下你当然还不适合成为老板！
大概就这样了吧 还有我就不知道了

这种句法是以which指代整个句子，叫非限制定语从句，通常which前面有逗号隔开。
比如
He gave me a toy bear as birthday present, which made me very happy.
It rained heavily this morning, which made me late for school.
指的是他送我玩具熊这件事让我高兴，早上下大雨这件事让我迟到了。
当然，which指代的是什么需要具体查看句子的意思。
比如同样的
He gave me a toy bear on my birthday, which is a present I was longing for.
I came across a tiger yesterday, which was trapped in a cage.
which指代的就是主句的a toy bear和a tiger

这里的 which 是关系代词，引导非限制性定语从句，但是 which 并不是指代名词 lady，而是指代整个主句的内容。