新概念英語第二冊語法精粹：名詞性從句（1）主語從句
知識要點：
名詞性從句包括：主語從句、表語從句、賓語從句和同位語從句。引導名詞性從句的連詞有：
A.連詞：that, whether, if（這三個詞都不作從句的成分，同時，that無含義，而whether和if都表“是否”）
B.疑問代詞：who, whom, whose, what, which
C.疑問副詞：when, where, why, how
（一）主語從句：在複合句中充當主語的從句。
引導主語從句
that引導主語從句時不同於其他的連詞，既無詞義也不作成分，只起單純的連接作用，且通常不可以省。爲了強調that引導的主語從句而置之於句首時，that不可省。
①That the driver could not control his car was obvious.
②That she was chosen made us very happy.
③That he will come is certain.
④That he would take the risk is true.
⑤That he should have married her isn't surprising.
★通常，that引導主語從句時用it做形式主語，把從句置於句尾，此時that有時可省。例如：
①It was obvious that the driver could not control his car.
②It made us very happy that she was chosen.
③It is certain that he will come.
④It is true that he would take the risk.
⑤It isn't surprising (that) he should have married her.
★如果以that從句爲主語的句子是疑問句，就只能用先行詞it結構。例如：
①Is it certain that he will come?
②Is it true that he would take the risk?
▲it做形式主語有以下幾種不同的結構：
(1)It + be + 形容詞+ that-從句
①It is likely that he will come.
②It is strange that she has ever trusted him.
③It is important that he (should) attend the meeting.
④It is best that he (should) go.
此句型在表示驚訝、喜悅、遺憾等感情色彩時，that從句中的謂語動詞也常用 (should) + v原形。
It is strange that no one should have objected to the plan.
(2)It + be +名詞+ that-從句
It is common knowledge that the whale is not a fish.
It's a pity that he should have catched the train.
(3) It + be + -ed分詞 + that從句
It is said that he is a famous writer.
It is reported that there will be a storm this afternoon.
▲在表示建議、要求、命令等意義的被動結構中，that從句中的謂語動詞常用(should) do。（參見虛擬語氣部分）
It is suggested that the meeting (should) be held this afternoon.
It is demanded that he (should) leave at once.
(4) It + seem/happen/appear等不及物動詞 + that從句。（look不接that從句，它接to be結構或形容詞）
It seems that he is wrong.
It appears that they are in urgent need of help.
He looks (to be) surprised/happy/sad.
2. whether引導主語從句，意爲“是否”，只起連接作用，不充當任何成分。（置於句首時必須用whether引導，置於句尾時，間或可用if。）
Whether he will win the game is not clear.
Whether he will come is uncertain.
Whether she comes or not doesn't concern me.
It is not clear whether/if he will come.
It was uncertain whether he would come.
3. 連詞代詞what, who, which, whose等引導的主語從句。這些連接代詞作用相當於代詞，在從句中擔當主語、賓語、表語、定語等。
What we need is more time.
Who was responsible for the accident is not yet clear.
Whose book it is not important.
Which school you want to go matters much.
4.連接副詞when, where, why, how引導的主語從句。這些連接副詞相當於副詞，在從句中充當狀語。
Why he did this is not known.
When he will come is still unknown.
It is not known why he did this.
How he succeeded is unknown to us.
Where we should hold the meeting needs to be discussed.
注意：wh-引導的主語從句也常用it作形式主語。
5.也可用whatever,whoever,whomever,whenever,wherever等詞引導主語從句，表示“無論什麼”、“無論誰”、“無論何時”、“無論在（到）哪裏”等。
Whoever told you to give up smoking was quite right.
Whatever he gave you should be handed in.
Whoever told you that was lying.
Whoever comes is welcome.
專項訓練：
1.______ makes mistakes must correct them.
A. What B. That C. Whoever D. Whatever
2. It worried her a bit ______ her hair was turning grey.
A. while B. that C. if D. for
and why he came here ______ yet.
A. is not known B. are not known C. has not known D. have not known
4.______ is no reason for dismissing her.
A. Because she was a few minutes late B. Owing to a few minutes late
C. The fact that she was a few minutes late D. Being a few minutes late
5.______Tom liked to eat was different from ______.
A. That…that you had expected B. What …that you had expected
C. That…what you had expected D. What…what you had expected
6.______ we go swimming every day ______ us a lot of good.
A. B. C. D.
______ Bob drives badly.
A. thinks that B. is thought what C. thought that D. is thought that
's uncertain ______ the experiment is worth doing.
A. if B. that C. whether D. how
9.______ the boy didn't take medicine made his mother angry.
A. That B. What C. How D. Which
10.______ we can't get seems better than ______ we have.
, what B. What, that C. That, that D. That, what
(後設答案，大家不要偷看(⊙o⊙)哦，(*^__^*) 嘻嘻……)
KEYS
1.C 2.B 3.A 4.C 5.D 6.D 7.D 8.C 9.A 10.A
