clauses and use them freely

课前自学（ SB P20-21 Discovering useful structures）

语法知识精讲

　　1．表语从句在复合句中作主句的表语。引导表语从句的连接词有：that ,whether, as if（仿佛）；连接代词有who, whose, what, which,连接副词有 when, where, how, why等。另外as, because，也可引导表语从句。表语从句位于连系动词后，有时用as if引导。其基本结构为：主语+系动词+从句。

　　常见的表语从句的句型有

　　This is because...

　　The reason for ...(why) is that...

　　He\ She looks as if ...

　　The trouble\problem is that...

　　例如:

The fact is that we have lost the game. 事实上我们已经输了这场比赛。

His suggestion is that no one (should )be allowed to smoke in the office.