在介词+which/whom结构中,介词一般由什么决定

1）介词与先行词的习惯搭配
There is no way in which it could be brought back to the earth．（in与way是习惯搭配）
2）介词与定语从句中的动词,形容词的习惯搭配
These are the wires with which different machines are connected．（be connected with是习惯搭配）
The author with whom all of us are familiar will visit our compa-ny．（be familiar with是习惯搭配）
3）同形的先行词,或定语从句中的动词,形容词表示不同的含义时,要根据其含义选用不同的介词.
I can't remember the age at which he won the prize．
That is the age in which people live in peace and happiness．
age在前句中意为“年岁”,与at搭配；在后句中意为“时期”,与 in搭配.
4）复杂介词须保持其完整形式,常见的复杂介词有on the top of,in the middle of,in front of,in spite of,at the back of,because of等.
We took a photo of rocket,the length of which was about 30me- tres．
Sound is a tool by means of which people communicate with each other．
They marched through the square,in the middle of which stood a monument．
5）短语动词中的介词不可与动词分开提至关系代词前.常见的短语动词有listen to,look at,depend on,pay attention to,take care of,look into,break into,get rid of,take part in,make use of,take hold of,catch hold of,catch up with,get along with,look forward to等.此时可用which,who,whom或that,也可将他们省略.
（误）This is the girl of whom he will take care．
（正）This is the girl whom he will take careof．
6）当介词与定语从句中的动词或形容词联系紧密（但不是短语动词）时,介词也可放在动词或形容词的后面.但当介词与从句中的动词或形容词联系不紧密时,则需将介词置于关系代词前.比较：
The space station which we drove to was in the desert．
I'll never forget the day in which I joined the Party．