名詞性從句是在句子中起名詞作用的句子。 名詞性從句的功能相當于名詞詞組， 它在復合句中能擔任主語、賓賓語從句語、表語、同位語、介詞賓語等，因此根據它在句中不同的語法功能，名詞性從句又可分別稱為主語從句、賓語從句、表語從句和同位語從句。

二、1.定義

賓語從句，是名詞性從句的一種。在主從復合句中充當賓語，位于及物動詞、介詞或復合謂語之后的從句稱為賓語從句。例如：

Looking at his watch, he saw that it was one o’clock.

看了看表，他注意到是一點鐘。

I was wondering whether I should bring my girlfriend to the gathering.

我在考慮聚會時是否應該帶女朋友過去。

I wonder why he deserted his enviable well-paid position.

我不明白他為什么要辭掉那個令人羨慕的高薪職位。

2.類型

(1)動詞的賓語從句

A. that引導(that通常可以省略)

He admitted that he had cheated.

他承認他作弊了。

The boy dreamed that he was flying to the outer space.

那個男孩夢見他正在飛往外太空。

B. wh-引導

She did not know what had happened.

她不知道發生了什么。

Nobody knew whether he could pass the exam.

沒人知道他是否會通過考試。

(2)介詞的賓語從句

Whether he can succeed depends on how well he operates.

他是否能夠成功取決于他的操作水平。

He was not conscious of what a big mistake he had made.

他沒有意識到他犯了一個大錯。

(3)形容詞的賓語從句

We are fully convinced that John was the winner of the speech contest.

我們完全相信約翰是此次演講比賽的獲勝者。

I am afraid that you’ve misunderstood your boss.

我擔心你誤解了你的老板。

(4)it可以作為形式賓語

We all thought it a pity that the conference has been cancelled.

會議被取消了，大家都覺得遺憾。

I think it necessary that we take plenty of hot water every day.

我認為每天多喝開水是有必要的。

3.例題

But it is useless to try to discourage someone, { [who feels that he must act], (though the chances of his becoming famous are slim ) }.

這是一個主從復合句。

原句中的各個子句，子句類型以及連接詞如下：

主句：it is useless to try to discourage someone

【譯文】試圖去阻止…的年輕人是徒勞的

分句一：who feels that he must act

類型：定語從句;連接詞：who

分句二：that he must act

類型：賓語從句;連接詞：that

分句三：though the chances of his becoming famous are slim

類型：讓步狀語從句;連接詞：though

【譯文】即使成名的機會很渺茫

【全句譯文】：試圖去阻止那些在成名的機會很渺茫的情況下仍然想要當演員的年輕人是徒勞的。