2、,但在从句中不担任成分。(二)主语从句1、主语从句在复合句作主语。e.g.Whowillgoisnotimportant.2、用it作形式主语,主语从句放在句末。e.g.Itdoesn’tmattersomuchwhetheryouwillcomeornot.3、that引导主语从句时,不能省略。e.g.Thathesuddenlyfellilllastweekmadeussurprised.注意:that从句作主语和宾语时,可以用it 来替换成以下几种结构表达。 (A)It is clear/certain/li
3、kely/true/surprising that… (B)It is a pity/shame/good idea/no wonder that ...(C)It is said/reported/ believed/known/thought/suggested that …(D)It seems/happens that。如: It happened that I went out last night. It is said that China will win in the World Cup. (三)
5、;(C)当that作介词宾语时,that不可省掉。如: He judged that,because he was a child, he did not understand wine Everyone knew what happened and that she was worried. The reason lies in that she works harder than the others do. 3、whether和if的用法。 1)whether和if在宾语从句中可以互换,但是作介词宾语时连接词
6、一般用whether。如: It all depends on whether they will come back. 2)后面直接跟or not 时用whether。如: I didn’t know whether or not he had arrived in Wuhan. 3)主语从句、表语从句、同位语从句中只能用whether。如: Whether the meeting will be put off has not been decided yet. The question is whether
7、they have so much money. We ought to discuss carefully the question whether we can do it or not. 4)whether常与or连用表示一种选择,if不能这样用The question of whether they are male or female is not important. 5)whether也可与动词不定式连用但if不能。如: I have not decided whether to go or not.
8、 6)宾语从句提前时用whether不用if。如: Thank you, but whether I’ll be free I’m not sure at the moment. 7)引导条件状语从句时,必须用if.Ifitrainstomorrow,wewon’tgototheSummerPalace.(五)同位语从句同位语从句在句中作某一名词的同位语,一