表语从句是怎么样的?

不能只看表语从句,要理解名词性从句
名词性从句
名词性从句相当于名词,作主句的主语、表语、宾语和同位语.因此,名词性从句分为主语从句、表语从句、宾语从句和同位语从句.
（一）引导名词性从句的连接词
1、连接代词：who[主语 ],whose [定语],whom[宾语],what [主语,宾语,表语],
which[定语].有词义,在从句中担任成分.
2、连接副词：when[时间状语],where[地点状语],why[原因状语],how[其他状语].
有词义,在从句中担任成分.
3、连接词：that,whether,if[是否],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.Who will go is not important.
2、用it作形式主语,主语从句放在句末.
It doesn’t matter so much whether you will come or not.
3、that引导主语从句时放在句首时,不能省略.
That he suddenly fell ill last week made us surprised.
（三）表语从句
1、表语从句在复合句中作表语,位于系动词之后.
The question was who could go there.
2、引导表语从句的连接词that有时可省去.
My idea is (that) we can get more comrades to help in the work.
（四）宾语从句
1、宾语从句在复合句中作宾语.引导宾语从句的连词that一般可省略.
I hope (that) everything is all right.
2、介词之后的宾语从句,不可用which或if连接,要分别用what或 whether.
I’m interested in what you’ve said.
3、whether与if常可互换.但下面情况不能互换.
①宾语从句是否定句时,只用if,不用whether.
I wonder if it doesn’t rain.
②宾语从句中的whether 与or not直接连用,就不能换成if；不直接连用,可换.
I don’t know whether or not the report is true.
I don’t know whether/ if the report is true or not.
（五）同位语从句
同位语从句在句中作某一名词的同位语,一般位于该名词（如：news,fact,idea,suggestion,promise等）之后,说明该名词的具体内容.
I have no idea when he will be back.
The fact that he had not said anything surprised everybody.