<例句>
Dancing bored him.
跳舞使他厌烦。
<语法分析>
动名词直接做主语。有时，动名词前可有一个代词或名词所有格表示其逻辑上的主语，有时还可名词化，前面带有冠词。句子的主语除了可用动名词表示之外，还可以用其他成分来表示，如数词、代词、名词、不定式、词组、从句或名词化的其他词类等。it可用作人称代词和非人称代词，也可用来对句子的某一成分加以强调。
<触类旁通>
(1)Are there other universes outside our own?
我们的宇宙之外还有别的宇宙吗?
语法分析：名词作主语。
(2)Nobody knows the answer.
没有人知道答案是什么。
语法分析：代词作主语。
(3)Two-thirds of them are college students.
他们中间三分之二是大学生。
语法分析：数词作主语。
(4)What she saw gave her a little fright.
她看到的情况使她吃了一惊。
语法分析：从句作主语。
(5)It's no use asking me.
问我没有用。
语法分析：先行词it作形式主语，真正的主语放在句子后面，从而使句子平稳。
(6)Who was it that called the meeting?
召集会议的是谁?
语法分析：用it对句子的主语加以强调，还可以强调其他成分。
<巩固练习>
(1)_____ [go] to the movies is a popular pastime.
(2)Their _____[come] to help was a great encouragement to us.
(3)It is any good _____[try]?
(4)It is an offence _____[drop] litter in the street.
(5)Not ______[be] punctual makes him unreliable.
(6)_____ was you who had been wrong.
(7)It costs 100 dollars _____[repair] the car.
<参考答案>
(1)Going (2)coming (3)trying (4)to drop (5)being (6)It (7)to repair
