1. 作表语：动名词作表语说明主语是什么或状态特征，如：
　　His hobby is collecting stamps.

　动名词作表语也能带有自己的逻辑主语，如：
　　What upset Mary was her not being allowed to see her mother in the hospital.

　动名词和不定式都可作表语，动名词表示比较抽象的一般行为，不定式表示具体某次动作，特别是将来的动作，如：
　　Her job is taking care of children.
　　Our task this afternoon is to move these chairs.

2. 作定语：动名词作定语放在所修饰的名词前面表示该名词的用途或与之有关的动作，如：
　a sleeping car 　　a walking stick
　a printing shop 　　a reading room
　a swimming pool 　　a washing machine
　building materials