subject cause
主语：n, pron, doing, to do, sentence
主从：简单句作为主语即为sc
特点：①形式主语it
a. it be +adj/n + 句子。
b. it be +vi（不及物动词） +句子 vi：seem, happen, matter…
c. it be + 句子。
it is said/decided/well known/believed that…..
谓语动词用单数。
a.主语从句多表示单一概念，因此主句谓语动词多用单数。如：
when and where we'll go isn't decided.
引导的主语从句，根据表达含义的不同确定主句谓语动词的单复数。如：
what we need are books/is water.
连词不能省略。
从句用陈述语序。
连词：无义，不能省略，不充当成分。
置于句首只能用whether “是否”，不充当成分。
疑问词包含意思，充当成分。
a关系代词 what/who 主/宾/表 which/whose
b关系副词 when/where/how/why 状语。
whoever/whatever/whenever/whichever/whomever
可填whoever都可填who
predicative clause
1. that引导的
that无意义，起连接作用，不可省略。
2. whether引导的。
是否，究竟”，起连接作用，不作任何成分。
eg：the chance is that one smoker in four will die from smoking.
the question is whether that man will turn up in time.
3. where, when, why, how引导的。
具有词义，在从句中充当状语。
eg：that’s where i cannot agree with you.
that is why she was late for the meeting.
that is how they overcome the difficulties.
my strongest memory is when i attended an american wedding.
4. as if, because, as, as though引导的。
because引导的只用于“this/that/it is because……”
as if/though 置于连系v：look, seem, sound, be, become等，常用虚拟语气，表示不存在的动作/状态。
it seem as if/though sb was knocking at the door.
5. whatever, however, whichever, wherever可引导n.从句。
whatever=anything that whoever=anyone who
缺状语可用：no matter who/what/ whoever/ whatever
却主语可用：whoever/ whatever
whoever/ whatever….可引导n.从句或让步状语从句。
no matter+疑问词只能引导让步状语从句。
eg：we will feel happy whoever/no matter who wins the game.
whoever wins the game deserves congratulations.
ps:1.表从的连词不能省略。
is why… 那就是….的原因 （表结果）
that is because…. 这是因为…….表原因）
eg：his mother is ill, that is why he is absent.
he is absent, that is because his mother is ill.
object clause
1.做v的宾语。
主谓宾 he doesn’t know where the post office is.
主谓间宾直宾 he told me what i should read.
主谓宾宾补 i find that he comes to me strange.
i find it strange that he comes to me. (形式宾语)
2.做prep.的宾语。
did she say anything about how we should do the work?
若跟在介词后，连词不能省略。
3.做adj.的宾语。
i’m sure that he can do it well.
i’m sorry that you are wrong.
ps:1)主句中主语是i, we的反意疑问以从句为主。
we believe that they h**e finished their task
2)that引导的宾从只有except, but, in, besides
eg: we couldn't h**e done it on time but that they hadn't come to help us.
3)不能省略的that：①介词后面 ②并列的宾从后。
eg：i said (that) he was right and that i knew him.
appositive clause
同位语：对一个n或一个pron进行修饰、限定或说明的叫同位语。
mr smith, our new teacher, is very kind to us.
we two had a talk privately.
all the chinese people, old and young, love our country.
同位语≠同从
i don’t know about the man, mr. white.
i don’t know about the fact that he is a teacher.
同从先行词必须为抽象n.
structures：
n. +连接词 + 从句 + 主句谓语。
function：表一个n.的具体内容。
n.抽象n：
suggestion/feeling/message/possibility/advice/fear/warning/reply/hope/story/wish【n.有demand,suggestion,proposal,advice等词后的同从用虚拟语气 （should）+do】
同从：定从的先行词n./pron.
同从的先行词，只能是n. 先行词放不回原句的是同从。
连词：不作成分：that（无义）/whether
主/宾：who, what, whom, which
状语：when, how, where, why
同从&定从的区别：
the news that he g**e me is true.
the news that they won is true.
所有同位语从句可改为表从：
the idea that they would cross the continent by train was exciting,the idea is that they would cross the continent by train.
ps:1.代词或数词作主语的同位语，谓语的数应和主语的人称和数保持一致。
this morning, our teacher g**e out the textbooks in class and now we each___h**e) a textbook.
the one作同位语的区别。
he offered the poor girl the baghis father bought for him yesterday.
second-hand smoking does cause us some health problems in fact far more serious,__than smoking itself does.
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