高中英语复习语法专练--名词性从句
2）That-从句作主语通常用it作先行词，而将that-从句置于句末，例如：
It is quite clear that the whole project is doomed to failure. 很清楚，整个计划注定要失败。
It's a pity that you should have to leave. 你非走不可真是件憾事。
用it作形式主语的that-从句有以下四种不同的搭配关系：
a. It + be +形容词+ that-从句
It is necessary that… 有必要……
It is important that… 重要的是……
It is obvious that… 很明显……
b. It + be + -ed 分词+ that-从句
It is believed that… 人们相信……
It is known to all that… 从所周知……
It has been decided that… 已决定……
c. It + be +名词+ that-从句
It is common knowledge that… ……是常识
It is a surprise that… 令人惊奇的是……
It is a fact that… 事实是……
d. It +不及物动词+ that-分句
It appears that… 似乎……
It happens that… 碰巧……
It occurred to me that… 我突然想起……
17.3 名词性wh-从句
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.
