主语从句讲解

5. It worried her a bit ___ her hair was turning gray. A. whether B. that C. what D. when
宾语
1)连接代词 what (whatever ),
连接代词引导主语从句，在句中作主语，宾语，表语， 定语。 Which side will win is not clear. 定语 Who will write the poem has not been decided yet.主语 Whatever he did is right. 宾语 What the city will be still remains a mystery. 表语
3）主语从句中用陈述语序 How he succeeded is still a puzzle.
4）主谓一致 主句谓语一般用单数形式。
1. “what”和“who”引导主语从句时，谓语动词的数与主 句中作表语的名词一致。 1. What you left are only several old books. 2. What you said is of great importance.
3.___ is known to us all that America is a developed country . A Which B As C What D It
4. It’s known to us all ___ a form of energy .
A. water is C. is water B. that water is D. that water to
“should + 动词原形”的形式, should有时可以省略。
改错练习
1.Where shall we spend the holiday isn’t decided. we shall 2.You have made a mistake is a fact. That you have
3.That is certain that we can win.
It is said that Mr. Green has arrived in Beijing.
D. It + 不及物动词或短语 + that 从句 ( seem，happen, doesn’t matter ,turn out） 。如： It happened that I was out that day.
We don’t know
主语从句后置!
为了避免主语冗长,句子头重脚轻,经常用 it 作 形式主语,主语从句放在后面作真正的主语. 例:
That we shall be late is certain. -- It’s certain that we shall be late. 1. That the earth is round is known to all.
It’s certain . we’ll be late. Is he coming or not ？
It’s certain that we will be late. That we’ll be late is certain. We don’t know whether he is coming or not . Whether he is coming is not known. What does he want to We don’t know what he wants to tell us. tell us? What he wants to tell us is not known. We don’t know When will you come back? It doesn’t matter. It doesn’t matter when you will come back. When you will come back doesn’t matter.
ቤተ መጻሕፍቲ ባይዱ
It doesn’t matter whether she will come or not.
注 意
1）主语从句在句首时，必须由连接词引导，不能省 略这些连接词。 误：They should like each other is natural. 正： That they should like each other is natural. It is natural that they should like each other. 2)如果主语从句放在句首，不能用if引导，但是如果用it 做形式主语，而把主语从句放在句末时，也可以用if引导. 误：If Mary really heard him is really doubtful. 正：Whether Mary really heard him is really doubtful. It was doubtful if Mary really heard him.
从属连词：that， whether 引导主语从句只起引导作用， 在主语从句中不充当任何成分，that本身无实际意义，但 不能省略. whether意为“是否”，放在句首句末皆可。
That price will go up is certain. That he will come is certain. Whether we go by train or by boat makes no difference. Whether he’ll come here isn’t clear.
总结：引导主语从句的连接词有： 从属连词: that, whether； 连接代词: who (whoever), whom, whose, what (whatever)和which (whichever)； 连接副词: when, where, how和why。
Make sentences :
2. 如果and 连接两个或者两个以上的主语从句作主语时， 谓语动词用复数；由两个或多个连接词引导一个主语从句 时，谓语动词用单数。
When they will start and where they will go have ____ not been decided yet.
has not been decided. When and where the meeting will be held ____
5) . 用于 It is important / natural / necessary / impossible that...句型中, 主语从句应使用虚拟语气,
用“should + 动词原形”的形式, should有时可以省
略。 6) . 在 It + be + suggested/advised/ordered/requested/ insisted/required 中, that从句的谓语也应该用
-- It’s known to all that the earth is round.
2. That you missed the chance is a pity. -- It is a pity that you missed the chance.
2. 用it 作形式主语的结构
A. It + be + 形容词 + that 从句 (obvious, true, surprising, good, wonderful, funny, possib le, likely, certain, probable, etc.) 如：
1. ___ he made an important speech at the meeting was true.
A. That B. Why C. What D. How 2. ___we’ll go camping tomorrow depends on the weather . A If B Whether C That D Where
Subject Clauses 主语从句
定义： 用作主语的从句叫主语从句,它是名词性从句之一.
What it was to become was uncertain until between 4.5 and 3.8 billion years ago when the dust settled into a solid globe.
Why they suddenly disappeared still remains a mystery.
3)连接副词when，where， how，why等, 在从 句中做状语。
How this happened is not clear to anyone. When he will be back depends on the weather. When we’ll start tomorrow will be told soon. Where the test will be given is not yet decided.
who ( whoever) , which (whichever), whom, whose .
The earth became so violent that it was not clear whether the shape would last or not. It was not immediately obvious that water was to be fundamental to the development of life. So whether life will continue on the earth for millions of years to come will depend on whether this problem can be solved.
It is certain that she will do well in her exam. B. It + be + 名词词组 + that 从句 (an honour, a fact, a pity, etc）如： It’s a pity that we can’t go.
C. It + be + 过去分词 + that 从句 (said, reported, thought, expected, decided, announced, etc。） 如：
表语
What is even more important is that as the earth cooled down, water began to appear on its surface.
主语
What many scientists believe is that the continued presence of water allowed the earth to dissolve harmful gases and acid into the oceans and seas.
It is 4.No matter who leaves the room last ought to turn off the lights. Whoever 5.If the policemen will come is not certain. whether
6.It is say that he was a famous writer. said 7.It is seemed that it is going to rain soon . seems 8.That is fact that she won the first place. It is a fact 9. Who leaves the room last ought to turn off the lights. Whoever 10.It is important that a student learns a foreign language. should learn