主語從句(Subject Clause)
定義:在復(fù)合句中充當(dāng)主語的句子叫做主語從句.
第一部分：常規(guī)主語從句,即句子在復(fù)合句中充當(dāng)一個(gè)主語
主語從句的時(shí)態(tài)：不受主句的時(shí)態(tài)影響和限制.
（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 hasn'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.
小結(jié):
（1)引導(dǎo)主語從句連詞有that,whether,who,what,whatever等
（2)連詞位于句首不能省略
（3)主語從句大多數(shù)情況下視為三單,但也有例外,如例9
第二部分：為了防止句子頭重腳輕,通常把形式主語it放在主語位置,真正主語擱置于句末
（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)
小結(jié):
（1)以that 引出的主語從句,常以形式主語it引導(dǎo). It is +形容詞/名詞/某些動(dòng)詞ed + that 從句.
（2) 在有些that從句中要用虛擬語氣 (should+do/should+have done)例句4,5,6,11.
主語從句與賓語從句兩者的用法和在句中的作用是不同的,下面從它們的各自用法,介紹：）~
一．主語從句
主語從句 定義:在句子中擔(dān)當(dāng)主語的是一個(gè)從句,這個(gè)從句就叫做主語從句.
主語從句是在復(fù)合句中充當(dāng)主語的從句,通常放在主句謂語動(dòng)詞之前或由形式主語it代替,而本身放在句子末尾.
1. It 作形式主語和it引導(dǎo)強(qiáng)調(diào)句的比較
It 作形式主語代替主語從句,主要是為了平衡句子結(jié)構(gòu),主語從句的連接詞沒有變化.而it引導(dǎo)的強(qiáng)調(diào)句則是對句子某一部分進(jìn)行強(qiáng)調(diào),無論強(qiáng)調(diào)的是什么成分,都可用連詞that.被強(qiáng)調(diào)部分指人是也可用who/whom.例如：
It is a pity that you didn’t go to see the film.
2. 用it 作形式主語的結(jié)構(gòu)
(1) It is ＋名詞＋從句
It is a fact that … 事實(shí)是…
It is an honor that …非常榮幸
It is common knowledge that …是常識(shí)
(2) it is ＋形容詞＋從句
It is natural that… 很自然…
It is strange that… 奇怪的是…
(3) it ＋不及物動(dòng)詞＋從句
It seems that… 似乎…
It happened that… 碰巧…
(4) it is＋過去分詞＋從句
It is reported that… 據(jù)報(bào)道…
It has been proved that… 已證實(shí)…
3. 主語從句不可位于句首的五種情況
(1) if 引導(dǎo)的主語從句不可居于復(fù)合句句首.
(2) It is said , (reported) …結(jié)構(gòu)中的主語從句不可提前.例如：
It is said that President Jingo will visit our school next week.
(3) It happens…, It occurs… 結(jié)構(gòu)中的主語從句不可提前.例如：
It occurred to him that he failed in the examination.
(4) It doesn’t matter how/whether …結(jié)構(gòu)中的主語從句不可提前.例如：
It doesn’t matter whether he is wrong or not.
(5) 含主語從句的復(fù)合句是疑問句時(shí),主語從句不可提前.例如：
Is it likely that it will rain in the evening?
4. What 與that 在引導(dǎo)主語從句時(shí)的區(qū)別
What 引導(dǎo)主語從句時(shí)在從句中充當(dāng)句子成分,如主語．賓語．表語,而that 則不然.例如：
What you said yesterday is right.
二：賓語從句的幾個(gè)特征：1、引導(dǎo)詞：what\which\whose\when\whether\if\where
2語序：賓語從句必須是用陳述語句.
如：I think that you must work harder.
賓語從句的引導(dǎo)詞、連接詞的區(qū)別、否定轉(zhuǎn)移等現(xiàn)象.
(1)表達(dá)時(shí)間的幾個(gè)句型：一般用when或者是what time：
What time will the train leave?
由于時(shí)刻都是固定的,也可以用一般現(xiàn)在時(shí)代替一般將來時(shí)：
What time does the train leave?
(2)時(shí)間的表達(dá)方式：8：19(nineteen past eight),7:57(three to eight),在時(shí)間的中間也可以加上分的單詞(minutes)
(3)had better +動(dòng)詞原型.意思是提要求,建議.但是上下級不能用這種方式,因?yàn)檎Z氣太重：
You had better give up smoking .
(4)sb leave sth +地點(diǎn)
I left my book in my classroom yesterday.
(5)may I have your name(address\age)?一般詢問對方的年齡、名字等,不要習(xí)慣以前的問法,這樣很不禮貌,而是要采訪上面的問法.以前的習(xí)慣是：how old are you? \what's your name?
(6)修飾名詞的代詞次序：限-描-大-形---年---顏----籍----物--------類+名詞：
this is a bridge.
This is a beautiful bridge
補(bǔ)充：從句的語序永遠(yuǎn)是陳述句.