3.2 动词不定式的否定形式：
not + to + 动词原形
The teacher told us not to swim in that river. 老师告诉我们不要在那条河里游泳。
It's unfair not to tell us. 没告诉我们真是不公平。
3.3 带疑问词的不定式：
　　疑问词 who, what,which,when , where, how, why 可以加在不定式的前面，构成不定式短语，使含义更加具体。
Where to go is not known yet. 去什么地方还不知道。
I don't know when to begin. 我不知道什么时间开始。
Can you tell me where to get the battery. 你能告诉我哪儿能买到电池吗？
Do you know how to get to the station. 你知道怎样去车站吗？
3.4 带逻辑主语的不定式：
　　动词不定式可以带有自己的逻辑主语，构成方法是：for + 逻辑主语 + 不定式。
　　注意：逻辑主语用宾格形式，for 本身无实际意义，它只表明后面的主语从逻辑上分析是不定式的主语。
It's necessary for us to help each other. 我们互相帮忙是必要的。
There are much work for me to finish, 有许多工作要我去完成。
3.5 动词不定式的时态：
　　动词不定式一般时：表示动作和句中谓语动词的动作同时发生或之后发生。
I helped him put the things into the car. 我帮助他把东西放进了汽车。
I want to see you again. 我想再见到你。
Would you like to have a rest. 你愿意休息一下吗？动词不定式完成时：表示动作在句中谓语动词的动作之前发生。
We are sorry to have kept you waiting so long. 对不起，我们让你久等了。
They seems to have known the answers. 他们好像知道了答案。
　　动词不定式进行时：表示动作同句中谓语动词的动作同时发生，强调动作正在进行。
They seem to be working hard. 他们好像在努力工作。
3.6 动词不定式的被动形式：表示不定式动词同所修饰的名词是被动关系 。
He is the man to be examined. 他是受检查的人。
There are much work to be done. 有好多工作要做。