"to"后面加的是动词的什么形式？
to后面接动词原形，构成动词不定式，to后面还可以接动名词，这时to作介系词来使用。
一、动词不定式的用法。
动词不定式是动词的一种非限定形式，由to加动词原形构成，在句中起名词、形容词和副词的作用，同时也保留动词的一些特征，可以带宾语、状语和宾语补足语等。
二、动词不定式的功能。
1. 作主语。
To think of you makes me old.
思君令人老。
It makes me old to think of you.
思君令人老。
It would be wrong for people to marry for money.
人们为钱结婚是错误的。
It was annoying of James to lose my bike.
詹姆斯弄丢我的自行车，真令人厌烦。
To see is not always to believe.
眼见不总为实。
2. 作表语。
My work is to prepare dinner.
我的工作是准备晚餐。
Little remains to do.
要做的事情几乎没有了。
3. 作动词宾语。有一些动词适合接不定式作宾语。
He likes to play baseball.
他喜欢打棒球。
I find it difficult to work with him.
我发现与他共事很难。
She made it a rule to get up at five.
她养成五点起床的习惯。
Never did I think to meet you here.
我从未想到会在那里见到你。
She doesn't care to spend much time with her relatives.
她不喜欢和亲属度过很多的时间。
4. 作介系词宾语。
It had no effect except to make her angry.
除了惹她生气之外，它没有效果。
My father being in poor health, I could do nothing but give up university.
我父亲身体不好，所以我只能放弃大学。
5. 作宾语补语。
I want you to tell me the truth.
我想要你跟我说实话。
What caused her to give up her studies?
什么让她放弃了学业呢？
I'll get the students to try again.
我要让学生再试一下。
I should dislike the students to smoke.
我不喜欢学生抽烟。
I know this to be a fact.
我知道这是事实。
Never have I known John tell a lie.
我从未见过约翰说谎。
有一些动词，如bid、have、let、listen to、look at、make后面的动词不定式是不带to的，叫做原形不定式。
