主从复合句
主句是主体，从句只是句子的一个成分，换言之，将句子（除谓语外）的各个成分扩展开来就成了从句。关联词分五类：
疑问代词：who（whom/whose），which, what,
关系代词：who（whom/whose），which, that,
疑问副词：when, where, why, how
关系副词：when, where, why
从属连词：that (无词义)，whether, if, although, after
because, before, when, since，
as soon as, as long as
只有从属连词没有句子功用，即不担任句子成分。
从句分为五类：
主语从句
宾语从句
表语从句
前三项都是名词性从句，句中作用如同名词。一般都不用逗号，所用关联词相同：1,连词that/whether/if
when /where /how /why（引导间接疑问句）
一．主语从句subject clause，也可分为三种：that引导的主从/ 由连接代副词引导的主从/ what和whoever等引导的主从。
1由that引导的主从，用得最多。(that 后面是主语)
“That she became an artist may have been due to her father’s influence.”她成为画家可能是受其父亲的影响。
上面句子看着别扭陌生，换成it引导的句子就熟悉了，因为一般除强调外都后置而由it代替，有五种形式：
（1）+ that 、、、
It is
（2）、、、
It’
（3）宾语) or adverbial(副词)) + that、、、
’re right.
It struck me that we ought to make a new plan. 我忽然想起我们应该制订一个新计划。
我从未想到或许她是在说谎
（4）、、、
It is said）that you was suffering from a stone in the kidney. 谣传说/据说你得了肾结石。
（5）、、、
’t be that they were interested in him. 不，不，他们不可能对他有兴趣。
口语中that可以省略：
显然他的话使她高兴。
Who is to be sent there hasn’t been decided.
It’s clear enough what he meant.
两种结构都能用，但是it结构更多，有四种形式。
why he behaved like tha t. 我不太清楚他为什么会这样做。
It’
where I live.
该发生的事总会发生。红色为从句
What is over is over. 过去的事就过去了。
Whatever my dad did was right. 俺爹做的都是对的。
Whatever she says goes. 一切她说了算。
Whoever comes will be welcomed. 谁来都欢迎
Whichever you want is yours. 你要哪个，哪个就归你。
二．宾语从句object clause.
1由that引导到宾从，有时that可省略
I suspected that it was a trick to get our money.
我怀疑这是一个骗我们钱的圈套
Who can guarantee that he’ll keep his word?
谁能保证他会遵守诺言？
You can depend upon it, I shall be there. 先行宾语(现行宾语中间要有逗号)
你放心，我会去那里的。
I take it they have left for home.
我猜想他们已经回家了。
2由连接代词或副词引导宾从
Write me how you got home. 写信告诉我你怎能到家的
Only you can decide who the best choice is.
只有你能决定谁是最佳人选。
I wonder what you call this stuff.
我想知道，你管这玩艺叫什么。
3由whether/if引导的宾从
I’m wondering whether you would care to spend the evening with me. 不知道你是否愿意跟我们共度今宵。
I asked her if I might call and see her. 我问她是否可以去看她。
4由关系代词what引导的宾从
Show me what you’ve bought.把你买的东西给我看看。
I could not express what I felt. 我无法表达内心的感受
As a friend of yours, I want to tell you what I hear.
作为你的朋友，我想把听到的事告诉你。
5作介词的宾从，其他从句这样用较少：
Don’t oke your nose into探听what doesn’t concern you. 别多管闲事。??
6 whatever/whichever/whomever这类词也可引导宾从：
I’ll just say whatever comes into my head.
想到什么就说什么。
Buy whichever is cheapest. 买最便宜的。
Give it to whomever you like. 你愿意给谁就给谁。
三．表语从句predicative clause，有二类
