本文目录
主语从句引导词都有哪些
引导主语从句连词有that,whether,who,what,whatever等
宾语从句：多为that,可以省略
表语从句：be动词的改变形势
定语从句：that,who,whom,whose,where,when,which...
状语从句：that,when,where等可以表示状态的疑问词等
主语从句(Subject
Clause)
定义:如果一个句子在复合句中充当一个主语,那么这个句子就是主语从句.
第一部分：常规主语从句，即句子在复合句中充当一个主语
（1）That
he
finished
writing
the
composition
in
such
a
short
time
surprised
us
all.
（2）Whether
we
will
go
for
an
outing
tomorrow
remains
unknown.
（3）Who
will
be
our
monitor
has't
been
decided
yet.
（4）
Whom
we
must
study
for
is
a
question
of
great
importance.
（5）What
caused
the
accident
remains
unknown.
（6）Whatever
you
did
is
right.
（7）Whose
watch
was
lost
is
unknown.
（8）What
we
need
is
time.
（9）What
we
need
are
good
doctors.
小结:
（1)引导主语从句连词有that,whether,who,what,whatever等
（2)连词位于句首不能省略
（3)主语从句大多数情况下视为单三,但也有例外,如例9
第二部分：为了防止句子头重脚轻，通常把形式主语it放在主语位置，真正主语搁置于句末
（1）It
is
certain
that
he
will
win
the
match.
（2）It
is
true
that
he
has
made
a
very
important
discovery
in
chemistry.
（3）It
is
very
likely
that
they
will
hold
a
meeting.
（4）It
is
strange
that
he
should
do
that.
（5）It
is
important
that
we
all
should
attend
the
meeting.
（6）It
is
strange
that
the
man
should
have
stuck
to
his
silly
ideas.
（7）It
is
a
pity
that
we
won't
be
able
to
go
to
the
south
to
spend
our
summer
vacation.
（8）It
is
still
a
mystery
what
caused
the
accident.
（9）It
is
said
that
he
has
gone
to
shanghai.(=He
is
said
to
have
gone
to
shanghai)
（10）It
is
known
to
all
that
the
gun
powder
was
first
invented
by
the
Chinese.
（11）It
is
suggested
that
the
work
should
be
done
with
great
care.
（12）It
seems
that
he
has
seen
the
film.(=He
seems
to
have
seen
the
film)
（13）It
happened
that
the
two
cheats
were
there.
(=The
two
cheats
happened
to
be
there)
小结:
（1)以that
引出的主语从句,常以形式主语it引导.
It
is
+形容词/名词/某些动词ed
+
that
从句.
（2)
在有些that从句中要用虚拟语气
(should+do/should+have
done)例句4,5,6,11
what引导的主语从句表语必须用todo
在下列情况下，作表语的不定式可以省略to：
主语部分含有实意动词 do，而且往往有all, the first, the only 等表示“所有”或“唯一”概念的词语，也包括what 引导的主语从句。在这种情况下，to 也可不省略。
实际上，what 引导的名词性从句中，what 这个词本身就带有“全部”的概念。
主语从句的引导词是如何选择
在英语中，主要有三大从句，即名词性从句（包括主语从句，宾语从句，表语从句，同位语从句）、形容词性从句（即定语从句）、副词性从句（即状语从句,包括时间、条件、结果、目的、原因、让步、地点、方式等）。
引导主语从句连词有that,whether,who,what,whatever等
定义:如果一个句子在复合句中充当一个主语,那么这个句子就是主语从句.
第一部分：常规主语从句,即句子在复合句中充当一个主语
（1）That he finished writing the composition in such a short time surprised us all.
（2）Whether we will go for an outing tomorrow remains unknown.
（3）Who will be our monitor has't been decided yet.
（4） Whom we must study for is a question of great importance.
（5）What caused the accident remains unknown.
（6）Whatever you did is right.
（7）Whose watch was lost is unknown.
（8）What we need is time.
（9）What we need are good doctors.
小结:
（1)引导主语从句连词有that,whether,who,what,whatever等
（2)连词位于句首不能省略
（3)主语从句大多数情况下视为单三,但也有例外,如例9
第二部分：为了防止句子头重脚轻,通常把形式主语it放在主语位置,真正主语搁置于句末
（1）It is certain that he will win the match.
（2）It is true that he has made a very important discovery in chemistry.
（3）It is very likely that they will hold a meeting.
（4）It is strange that he should do that.
（5）It is important that we all should attend the meeting.
（6）It is strange that the man should have stuck to his silly ideas.
（7）It is a pity that we won't be able to go to the south to spend our summer vacation.
（8）It is still a mystery what caused the accident.
（9）It is said that he has gone to shanghai.(=He is said to have gone to shanghai)
（10）It is known to all that the gun powder was first invented by the Chinese.
（11）It is suggested that the work should be done with great care.
（12）It seems that he has seen the film.(=He seems to have seen the film)
（13）It happened that the two cheats were there. (=The two cheats happened to be there)
小结:
（1)以that 引出的主语从句,常以形式主语it引导. It is +形容词/名词/某些动词ed + that 从句.
（2) 在有些that从句中要用虚拟语气 (should+do/should+have done)例句4,5,6,11.
一、名词性从句概说
名词性从句，即指性质相当于名词的从句，它包括主语从句、宾语从句、表语从句和同位语从句。从高考的考查的实际情况来看，名词性从句考得最多的是宾语从句，其次是主语从句，再次是表语从句，而同位语从句则很少考查。
二、名词性从句的一般引导词
1.连接词that 引导名词性从句时，只起连接作用，没有任何意思，也不充当句子成分，在宾语从句中可省略，但引导其他名词性从句时通常不省略。如：
I hope (that) you enjoy your holiday.希望你假期过得好。
That he likes you is very obvious.很显然他喜欢你。
2.连接词whether 引导名词性从句也不充当句子成分，但有自己的意思，表示“是否”；引导宾语从句时，可换成if，但引导其他名词性从句时不能换成if。如
He asked whether [if] I would show him the way.他问我是否可以给他带路。
Whether it will do us harm remains to be seen.是否对我们有害还要看一看。(引导主语从句，不能用if代替whether)
3.连接代词who(m), whose, which, what等引导名词性从句时，均有各自的意义，在从句中作主语、宾语、定语等。如：
That’s why she wanted to leave.这就是她想离开的原因。
When we arrive doesn't matter.什么时候到没有关系。
Tell me which one you like best.告诉我你最喜欢哪一个。
4.连接副词when, where, why, how等引导名词性从句，也各自有自己的意义，在从句中作状语。如：
The question is how we should carry out the plan.问题是怎样执行这个计划。
When she’ll be back depends much on the weather.她什么时候回来在很大程度上要看天气。
Why he did it will remain a puzzle forever.他为什么这样做将永远是一个谜。
三、名词性从句的重要引导词
1.what用于引导名词性从句是一个十分重要的引导词，它可引导主语从句、宾语从句和表语从句，但不用于引导同位语从句。它引导的名词性从句有两个意思是：一是表示“什么”，带有疑问意味；二是表示“…所…的”，相当于一个先行词后接一个关系代词。如：
I don’t know what you want.我不知道你想要什么。
I don’t know what you want is this.我不知道你所想要的是这个。
2.what引导名词性从句时可用作限定词，其后修饰名词。如：
I gave him what books I had.我把我所有的书都给他了。
He gave me what money he had about him.他把身边带有的钱全给了我。
注：what后的名词可以是复数名词或不可数名词，但通常不能是单数可数名词，并且后接不可数名词时，有时可有little修饰，两者的区别是：what+不可数名词=所有的都，what little+不可数名词=虽少但全部。如：
What friends she has are out of the country.她有的那些朋友全在国外。
We gave him what (little) help we could.我们给了他我们力所能及的帮助。
3. whoever, whatever, whichever 等也可引导名词性从句，其意分别为“所…的一切事或东西”、“任何…的人”、““…的任可人或物”等。如：
Whoever wants the book may have it. 任何人要这书都可拿去。
I’ll do whatever I can to help him. 我们将尽我们所能来挽救他。
Buy whichever is cheapest. 买最便宜的。
注意以下受汉语意思影响而弄错的句子：
误：Who comes will be welcome. / Anyone comes will be welcome.
正：Whoever comes will be welcome. / Anyone who comes will be welcome.
另外，它们也可引导让步状语从句，其意为“无论…”、“不管…”，其意相当于 no matter who [what, which]。如：
Whatever happens, you must be calm. 不管发生什么情况，你都必须镇静。(whatever = no matter what)
He won't eat you, whoever he is. 不管他是谁，他也不能把你吃掉。(whoever = no matter who)
注：whoever 引导名词性从句时既用作主格也用作宾语；作宾语时不宜用 whomever，因为在现代英语中 whomever 这个已几乎废弃不用。
4. why 与 because 的用法区别。两者均可引导表语从句，但前者强调结果，后者强调的原因。如：
I had a cold. That’s why I didn't come. 我感冒了，因此我没来。
I didn’t come. That’s because I had a cold. 我没有来，那是因为我感冒了。
主语从句宾语从句表语从句定语从句的区别
1）由连接代词who、whom、what、which、whose、how much、how many 引导的名词性从句
上面列出的连接代词代替从句中的名词或修饰名词的词,有实际词义,不能省略.
who -------------- 人（主格,也可用于宾格）
whom ------------ 人（只用于宾格）
what -------------- 物（主格或宾格）
which ------------ 哪一个（名词的定语）
whose ------------ 谁的（名词的定语）
how many(much) 多少(代替名词或做名词的定语)
2）由连接副词where,when,why,how,how often引导的名词性从句
上面列出的连接副词代替从句中副词或介词短语,有实际意义,在从句中做状语,不能省略.
where ------------ 地点
when ------------- 时间
why -------------- 原因
how -------------- 方式
3）由关系代词引导的定语从句
who代替人,在从句中做主语或宾语.
which代替物,在从句中做主语或宾语.
whom代替人,在从句中做宾语.
that可以与who which whom换用.
4） 关系副词引导的定语从
When-----代替时间
Where-----代替地点
Why-----代替原因
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