(1)时态

　　①一般式：动名词的一般式所表示的动作可以是泛指，也可与谓语动词同时发生，或发生在谓语动作之前 、之后。如：

　　We are interested in collecting stamps.

　　I shall never forget seeing the Great Wall for the firsttime.

　　We are not afraid of dying.

　　②完成式所表示的动作发生在谓语动词之前。如：

　　Lmagine having travelled on the moon.

　　We were praised for having finished the work ahead of time.

　　(2)被动语态

　　①如果动名词的逻辑主语为动名词所表示的动作的承受者，动名词要用被动语态，动名词的被动语态有一 般式与完成式之分。如：

　　The young man came in without being noticed.

　　He prided himself on having never been beaten in class.

　　②有些动词后的动名词用主动形式，但表示被动意义。如：

　　The bike needs repairing.

　　If a thing is worth doing, it is worth doing well.

　　⒋在口语中，为避免重复，常用"to"代替不定式结构，有时甚至可以把to省略。如：

　　①—Did you go to visit the Great Wall?

　　—No,I wanted to,but there wasn't enough time.

　　②—Would you like to come to a party?

　　—I'd love to.

　　③—Don't make any mistakes in your homework,will you?

　　—I'll try not to.

　　④—Try to be back by 12,won't you?

　　—OK,I'll try.

　　另外，be going to,ought to,used to等也常用于这一结构中。

　　⒌在why引起的问句中，省略"to"。如：

　　Why spend such a lot of money?

　　Why not wait for a couple of days?

　　⒍当两个或更多作用相同的不定式并列使用时，只在第一个不定式前加"to"。如：

　　It's quite necessary for us to read more and have morepractice.

　　⒎"to"在下列短语中是“介词”，后接动名词或名词形式。如：

　　devote…to,face up to(勇敢地面对)，look forward to(盼望)，object to(反对)，take to(养 成习惯，对……感兴趣;开始从