定语从句问题，英语高手请帮忙

the field in which we can cooperate/This is the house in which he lived two years ago这两句都是定语从句。in which 这种用法只能用于定语从句，不能
用于地点状语从句. 定语从句中的结尾可以为介词。
He is the man whom I need to take care of.(定语从句)
we cross the stream where it is shollowest.(状语从句)
我们从小溪最浅处淌过
we cross the stream that is shollowest.(定语从句)
我们淌过最浅的小溪
you 'd better make a mark where you have any question.(状语从句)
This is the farm where/on which I worked ten years ago.(定语从句)

通俗的说法。。。
定语，就是对一个词的修饰，所以定从前面一定有个被修饰的词语
状语，包括时间地点状语等等，所以前面不需要有被修饰词语

你看第一个句子The field in which we can cooperate。此处的in which,理解有误，并不是那个可以=where的词组，而是The field which we can cooperate in,"cooperate in"才是一个搭配，就好像the city which we lived in，the pen which i wrote with.所以就是定从咯~
第2个句子This is the house in which he lived two years ago.这里就是真正的=where，哇靠。。。我也晕了。。。。

对不起。。抢版面了。。各位大虾加油。。。

定语从句的结尾可以是介词，但是这种情况下一般会把介词提前到which这些词的前面，the field in which we can cooperate说成是 the