in which(which引导的定语从句和in)

区别在于后面的定语从句缺少不同的状语。因为这些介词加关系代词中间的介词很多是由定语从句决定的，which指代前面的先行词。其中包含固定词组，要么和先行词构成固定搭配后在定语从句里做状语；要么和定语从句的谓语构成固定搭配做定语从句的状语。

in which：在......里。

for which：为了......；因为.....。

on which：关于......；在......上。

at which：（具体）在......（年龄/地点等等）。例如：

Select the database in which you want to compare counters.（ in which在定语从句里做地点状语）

选择您想要在其中比较计数器的数据库。

This is an emerging space in which we will likely be seeing some innovation over thecoming months.（ in which在定语从句里做地点状语）

这是一个新兴空间，关于这方面，在未来的几个月我们将能看到一些创新。.

That is the reason for which he dislikes me.（for which在定语从句里做原因状语）

这就是他不喜欢我的原因。

It would work and serve the specific purpose for which it was created, but it would do little to deliver on the original promise of SOA as it had been envisaged several years earlier. （for which在定语从句里做目的状语）

没错，它能完成一定的功能并满足最初的特定目标，但至于履行已展望多年的SOA最初承诺，它就不行了。

The material on which an autograph was signed, and whether the star was living ordead, could have as much of an impact as who signed it.（on which在定语从句里做地点状语，sign on：在......签字）

有明星亲笔签名的那些东西和给这些东西签名的人物具有同样大的影响力，不管这些明星是活着还是已经死了。

Where the analysts seem to have gone off the rails last year is in the price-to-earnings multiples on which they based their predictions.（on which在定语从句里做地点状语，词组base......on......：把什么建立在.....上）

然而，分析师们当时似乎在市盈率倍数这个他们赖以进行预测的关键数据上出了岔子。

Study of the bones of these cattle from ancient times shows the ages at which the animals were killed.（在定语从句里做时间状语，at the age of：在....岁时）

对于这些远古时期驯化牛骨骼的研究结果告诉了我们这些家畜宰杀时的年龄。

这里in which 引导的是定语从句， 修饰days , in which 相当于 when , 在从句中作时间状语， 不能直接用which ， which 在从句中是充当主语或宾语的。