I can’t imagine the reason【why】heturned downmy offer.
可用for which
二、如何使用宾语从句、主语从句、表语从句和同位语从句的引导词
引导词
作用
例句
That
相对不缺少成分；陈述语气
I knewthatyouwerehere[just now].
If
Which
缺少定语，（指物、人）
He’ll buy(which) bookheis interested in.
whose
缺少定语，（指人）
She askedwhose jacketitis.
三．并列句和状语从句的连接词
连
词
并
列
连
词
同等关系
and\both---and
neither---nor、 not only---but also
as做宾语一般不省略
关系副词
when
时间
缺少时间状语
I will never forget the day【when】wemet【there】.
可用on which
where
地点
缺少地点状语
This is the house【where】Iwas born.
可用in which
why
原因
缺少原因状语
The picturewhichwas aboutthe accidentwas terrible.缺少主语
as
人或物
缺少主语，宾语
He is such a personasis respected【by all of us】.缺少主语
This is the same penasIlost【yesterday】.缺少宾语
en
缺少时间状语
He told me [when ]wewould gather.
Where
缺少地点状语
Can you tell me[where]helived?
Why
缺少原因状语
He wanted to explained[why]hewaslate.
How
缺少方式状语
Can you tell me [how]youwantyour tea?
whom
人
缺少宾语
Mr. Smith is the personwith whomIam working
The boy(whom)sheloveddied in the war..
whose
人或物
缺少定语
I like those bookswhose topicsare abouthistory.
The boywhose fatherworks abroadis my deskmate.
2.I sold forwhatwasenough
3.He’s ready to accept(whatever) helphecan
get.
Who
缺少主语，（指人）
I wanted to knowwhowill come.
Whom
缺少宾语，（指人）
I don’t knowwhomyou’re waiting for.
各种从句引导词总表
一、如何选择定语从句的关系词
关系词
先行词
从句成分
例句
备注
关系代词
who
人
缺少主语
Do you know the manwhois talking withyour mother?
whom, which和that在从句中做宾语时，常可以省略，但介词提前时后面关系代词不能省略，也不可以用that
条件
If\unless\so long as\in case
让步
Though\although\no matter---\even if
方式
as(按照)\as if\as though
比较
as---as\not so---as
结果
So---that\such---that
目的
inorder that
that
人或物
缺少主语，宾语
A plane is a machinethatcan fly.缺少主语
She is the pop star(that)Iwant to see【very much】.缺少宾语
which
物
缺少主语，宾语
The book (which)Igaveyouwas worth $10.缺少宾语
Whether
相对不缺少成分；疑问语气
从句的谓语动词为：ask;question;wonder---
I doubtif\whetherhecan doit[well now].
What
Whatever
缺少主语，宾语，定语
（指物）
1.You can be sure ofwhatyouhave[at present].
转折关系
but\however\yet\while
选择关系
Or\either---or
因果关系
So\therefore
从
属
连
词
状
语
从
句
时间
when\while\since\as\till\until
before\after\whenever
地点
where\wherever
原因
because\as(由于)\since（既然）