表语从用法
1.定义：用作表语的从句叫做表语从句
2.引导表语的从句的关联词的种类
（1）从属连词that. The trouble is that I have lost his address.乌拉草床垫
The reason was that he was late for school。
（2)从属连词whether, as, as if
He looked just as he had lookedten years before。
The question is whether they will be able to help us。
注:从属连词if一般不用来引导表语从句，但as if却可引导表语从句。All this was over twenty years ago, but it's as if it was only yesterday.
The key is whether we can solve the problem.
It looked as if it was going to rain.
注：能跟表语从句的谓语动词一般为系动词be， em， look， sound等
He looked just as he had looked ten years before。
It sounds as if someone is knocking at the door.
(3) 连接代词who, whom, who, what， which, whoever， whatever, whichever 在表语从句中做主语、宾语等。
The problem is who we can get to replace her.
That was what she did this morning on reaching the agreement。
My question is who left。
(4） 连接副词where， when， how, why
What I wonder is when he left。 This is where they once lived.
That is why he didn’t come here。
The question is how he did it.
（5） 连词becau 可引导表语从句。注意：becau 可引导表语从句，但与之同义的since, as， for等不用于引导表语从句.
I think it is becau you are doing too much。
It’s just becau he doesn’t know her.
That’s becau he didn’个人事迹简介500字t understand me.(That's becau…强调原因）
That’s why he got angry with me。（That’s why…强调结果）
水晶套注意：在一些表示“建议，劝说，命令”的名词后面的表语从句中，谓语动词用虚拟语气. Should+动词原形表示，should可省略。
My suggestion is that we （should) start early tomorrow.
一坚持（insisit）二命令（command， order）三建议(suggest， advi， propo）四要求(desire, demand, require， request)
四．注意事项（重点看）
1。 表语从句要用陈述语序.
That is where the famous scientist was born。
This is why she is so happy today.
2.that和what在引导的表语从句
that本身没有词义，在句中只起连接作用，不充当句子成分;what则表示“所…的（人或事）”,在表语从句中充当主语或宾语等。
That facet is that more than venty percent of the earth's surface is covered by water。
孕妇我最大>小酥肉的正宗做法What he told you was what had been discusd at the meeting。
人声朗读
3.if与whether均意为“是否”引导的表语从句是,只能用whether，不能用if。The question is whether we can finish our work by tomorrow evening.
4.语气
（1）主语为advice， order， idea， notion, proposal， suggestion， request等一些表示“建议，劝说,命令”的名词，之后的表语从句中，谓语动词用虚拟语气。Should+动词原形表示，should可省略。
My suggestion is that we （should） start early tomorrow。
Our only request is that this should be ttled as soon as possible。
(2) as if / though引导的表语从句时,从句谓语多用虚拟语气。这是因为从句中的情况与事实不相符。
具体来说,如果从句表示与现在事实相反，谓语动词用一般过去式；如果从句表示与过去事实相反，谓语动词“had+done波兰旅游”,如果从句表示将来的可能性不大，用would（might， could)+动词原形。
insole
Li Lei is now in a new jacket he looks as if he were an American boy.
The girl is giving us a vivid description of the moon。
It ems as if she had been to the moon many times。
但是,如果as if， as though引导的表语从句所表示的与事实相符，从句则用陈述语气。
The clouds are gathering. It looks as if it is going to rain.
