一. 作主语
1. 直接位于句首
eg. Swimming is a good sport in summer.
2. 用 it 作形式主语，把动名词(真实主语)置于句尾作后置主语。
eg. It is no use telling him not to worry.
* important，essential，necessary 等形容词不能用于上述结构。
3. 用于“There be”结构中
eg. There is no saying when he'll come.
4. 动名词的复合结构作主语:当动名词有自己的逻辑主语时，常可以在前面加上一个名词或代词的所有格，构成动名词的复合结构, 动名词疑问句通常使用这种结构做主语
eg. Their coming to help was a great encouragement to us.
Does your saying that mean anything to him?
二. 作宾语
1. 作动词的宾语
某些动词后出现非限定性动词时只能用动名词作宾语，不能用不定式。不定式通常指某种特定的动作，但动名词表示泛指，常见的此类动词有：
admit,appreciate,excuse,stand,advise,allow,permit,avoid,consider,enjoy,finish,give up,cannot help,imagine,include,keep,understand,keepon,mind,report,risk,miss,put off,delay,practise,resist,suggest,depend on,think about,set about,succeed in,worry about,burst out,insist on,feel like,be used to,get used to,devote…to…，look forward to,pay attention to,get down to,escape and so on.
eg. They went on walking and never stopped talking.他们继续走，说个不停。
2．作介词的宾语
动词+介词+动名词
eg.The rain prevented us from finishing the project.
形容词+介词+动名词
eg. I know who is responsible for breaking the window.
名词+介词+动名词
eg. We are thinking of making a new plan for the next term.
3．作形容词的宾语
eg. We are busy preparing for the coming test.
三. 作表语：动名词作表语时句子主语常是无生命的事物的名词或what引导的名词性从句。表语动名词与主语通常是对等的关系，表示主语的内容，主语、表语可互换位置。如果句中的主语和表语同为动词时，要注意保持两个动词在形式上的一致。
eg. Your task is cleaning the windows.
四. 作定语: 动名词作定语往往表示被修饰词的某种用途。如：
eg. a reading room.（a room for reading）
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