第九章：主语从句

名词性从句
在句子中起名词作用的各种从句统称为名词性从句。

根据它们在句中的语法作用，这类从句又可分为主语从句、宾语从句、表语从句和同位语从句。

1. 主语从句
主语从句有三种类型
①由that 引导的主语从句，that 在句中无含义，不担当任何成分，不可以省略。

例如：That he won the first prize in the competition seemed unlikely.
他在比赛中获得第一名是不可能的。

That you are so indifferent really annoys me.
你如此冷淡惹恼了我。

That she survived in the air crash was a real miracle.
她在飞机失事中幸免于难简直是奇迹。

②由连接代词或副词引导的主语从句。

Why he did that wasn’t very clear enough.
Whether she can come or not is not my concern.
Who will be sent abroad to study hasn’t been decided yet.
③由关系代词what 引导的主语从句。

What he said was wrong.
What I want to be in the future is a scientist.
注意：主语从句常用it作形式主语，将that 引导的从句位于句末。

That he became a musician surprised all of us.
It surprised all of us that she became an artist.
其中几种特殊的句式：
①It + be + 形容词/名词+ that
It is certain that we will win the game.
It is a pity that Professor Wang can’t come to the lecture.
②It + is/was + 过去分词+that结构。

常用语这种结构的有动词say, think, consider, estimate, regard等。

It is reported that there has been a terrible earthquake in Japan.
在这种结构中，that 从句的谓语也可以用“虚拟语气should +动词原形”表示建议、命令、要求等，should 常可以省略。

It is suggested that we should go for an outing.
练习：选择题。

1. _____ as much as one-fifth of all timber harvested is not used.
A. The estimate
B. The estimate
C. They are estimated
D. It is estimated that
2. _____ she had forgotten to take her notebook.
A. That occurred to her
B. She occurred that
C. To her that occurred
D. It occurred to her that
1._____ or not is still uncertain.
A. He’s coming
B. If he is coming
C. That coming
D. Whether he’s coming
4. _____ he saw both surprised and frightened him.
A. That
B. When
C. What
D. Which
5. _____ book you borrow must be returned within a week.
A. What
B. Which
C. Whichever
D. That’s。