[观察例句]
1．Every artist's wish is to create something that expresses an idea.
2．One way for him to find inspiration is turning to his children's toys.
3．Yang Liping's passion is dancing.
[归纳用法]
1．不定式作表语常表示具体的动作，尤其是某一次的动作。
His teaching aim of this class is to train the students' speaking ability.
他这节课的教学目的是要训练学生说的能力。
2．ing作表语，有两个特点：
(1)表示抽象的、概念性的动作，可以是多次的、经常性的。
Its fulltime job is laying eggs.
它的(指蚁后的)专职工作是产卵。
