动词不定式的一般形式是“to＋动词原形”，但在下面情况中to要省略：

一、在感官动词see, hear, watch, notice, feel, look at, listen to等及使役动词make, let, have等后作宾语补足语的动词不定式要省略to。如：

We saw him get on a bus.

The boss often made the workers work for over 12 hours a day.

注意：以上情况如果用于被动语态时，不定式符号to一定要补回。如：

He was seen to get on a bus.

The workers were often made to work over 12 hours a day.

二、在动词help后作宾语补足语的动词不定式符号to可带可不带。如：

I often help my mother (to) do housework.

三、在had better, would rather后动词不定式不能带to。如：

You’d better not go out at night.

The boy would rather stay at home by himself.

四、当两个或两个以上的动词不定式并列使用时，通常只有第一个不定式前带to，第二个及以后的不定式可省略to。如：

I want to have a read and write.

He wants to have a rest and have a cup of tea.

五、“Will(Would) you please＋不带to的不定式”。如：

Would you please not do that again?

六、当不定式作介词but, except的宾语，表示“除了……不/没有做……”时，不定式要省略to。如：

She does nothing but watch TV.

She doesn’t want to do anything except sleep.