三让：have, let, make;
二听：hear, listen to;
一感觉：feel;
一注意：notice。如：
This picture makes me feel excited!
这幅画使我感觉很兴奋。
We saw Liu Yu play baseball last week.
上周我们看到刘宇打棒球了。
(3)help后接动词不定式作补语，to可带可不带。
They can help you (to) learn English.
他们帮助你学习英语。
6. 用作状语
(1)目的状语，置于句首或句末，置于句首时常表示强调。如：
In order to catch the early bus, she got up very early.
为了赶上早班车，她起得很早。
A group of young people got together to discuss this question.
一组年轻人聚在一起讨论这个问题。
She came to this city to visit her daughter.
她来到这个城市看望她的女儿。
(2)原因状语，多见于sb.+be+adj.+to do...结构句中。如：
I feel very lucky to have him.
拥有他我感觉很幸运。
(3)结果状语，多见于too...to，enough to...结构句中。如：
Im too tired to do it well.
我太累了以至于做不好这件事。
The room is big enough for three people to live in.
这个房间三个人住足够大。
7. 动词不定式的复合结构
动词不定式的复合结构是for / of sb. to do sth.。不定式复合结构的介词用for还是of，主要取决于前面形容词的性质。一般说来，of前面的形容词是careful, clever, foolish, good, kind, nice, wise等，说明人的特性;for前面的形容词是dangerous, difficult, easy, hard, heavy, important, interesting, necessary等，一般说明不定式动作的特性，前面如果是名词用for。如：
Its a good idea for parents to allow children to study in groups during the evening.
对父母来说，在晚上让孩子分组学习是个好主意。
Its wise of him to do it well.
对他来说，把这件事做好很明智。