引導(dǎo)主語從句連詞有that,whether,who,what,whatever等
定義:如果一個(gè)句子在復(fù)合句中充當(dāng)一個(gè)主語,那么這個(gè)句子就是主語從句.
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
（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)情況下視為單三,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.