有哪些定语从句中介词或副词不能提前的固定短语动词？

凡是结构紧密含介词的短语动词，在定语从句中不能把介词提前到关系代词前，例如 look after, look for, take care of, be afraid of，等等。
但是，由于所有的与介词同形的小品副词都不能提前，因此不包括副词一说。

哪些短语动词在定语从句中不可将介词或副词与动词分离
1.含有介词的动词短语固定搭配一般不拆开使用,如：look for,look after,take care of等
(1) This is the watch which/that I am looking for.(T)
(2) This is the watch for which I am looking.(F)
2.若介词放在关系代词前,关系代词指人时用whom,不可用who或者that；指物时用which,不能用that；关系代词是所有格时用whose
(1) The man with whom you talked is my friend.(T)
(2) The man with that you talked is my friend.(F)
(3) The plane in which we flew to Canada is very comfortable.(T)
(4) The plane in that we flew to Canada is very comfortable.(F)(这里的talk with sb,fly in the plane,并不属于固定搭配,是直接就可以凑成的搭配,所以其介词可以提前)。

定语从句中介词不可以提前的短语
关系代词在定语从句中用作介词宾语时，介词既可置于从句之首，亦可置于从句之末。但以置于从句之首较为正式。如：
This is the book for which you asked. 这是你所要的书。(关系代词用作介词for宾语，介系词for放在从句的开头，即which之前)
This is the book which you asked for. 这是你所要的书。氏判拿(介词for置于从句之末，歼搭which在此可省去)
如果介系词与动词或形容词组成固定词组时，介系词就不可以提前了，如：冲高
The old woman whom he is taking care of is my grandmother. 他正在照顾的那位老人是我的外婆。
关系代词who和that用作介词宾语时，介词须置于句末。如：
The people who you were talking to are Swedes. 你与之谈话的那些人是瑞典人。(关系代词主格who用作介词to宾语时，介词to须置于从句之末，who中口语中可省去)
Here is the car that I told you about. 这儿就是我和你谈过的那辆汽车。(关系代词that用作介词about宾语，介词about须置于从句之末)
有时从句还有其它成分，介词则置于从句之中。如：
This is the boy whom he worked with in the office. 那就是与他一道办公的那个男孩。