1)由wh-词引导的名词从句叫做名词性wh-从句。Wh-词包括who, whom,. whose, whoever, what, whatever, which, whichever等连接代词和where, when, how, why等连接副词。Wh-从句的语法功能除了和that-从句一样外，还可充当介词宾语、宾语补语和间接宾语等，例如：

主语： How the book will sell depends on its author.　书销售如何取决于作者本人。

直接宾语：In one's own home one can do what one likes.　在自己家里可以随心所欲。

间接宾语：The club will give whoever wins a prize.　

表语： My question is who will take over president of the Foundation.　我的问题是谁将接任该基金会主席职位。

宾语补足语：She will name him whatever she wants to. 她高兴给他起什么名字就取什么名字。

同位语：　　I have no idea when he will return.　

我不知道他什么时候回来。

形容词宾语：I'm not sure why she refused their invitation.　 我尚不能肯定她为什么拒绝他们的邀请。

介词宾语：　That depends on where we shall go.　

那取决于我们去哪儿。

2)Wh-从句作主语也常用先行词it做形式主语，而将wh-从句置于句末，例如：

　It is not yet decided who will do that job.　

　还没决定谁做这项工作。

　It remains unknown when they are going to get married.　 他们何时结婚依然不明。

if, whether引导的名词从句