1.stop to do sth. 和stop doing sth.
stop to do sth。 表示停止做其它事情而去做to do sth。所表示的事情，可以将to do sth。理解成stop的目的状语;stop doing sth。表示不做doing sth。所表示的事情。
例如： Stop talking. Lets begin our class。 said the teacher. 老师说：别说话了，让我们开始上课。
We have kept doing our homework for a long time. Lets stop to listen to music. 我们做家庭作业很长时间了，让我们停下来听听音乐。
2.forget to do sth。和forget doing sth. (remember to do sth. 和remember doing sth。)
forget to do sth。表示将来不要忘记做某事，谈的是未来的事情;forget doing sth。表示忘记过去应该做的事情。
例如： Dont forget to do your homework。 said the teacher before the class was over.
老师在下课前说：不要忘记做家庭作业。
m sorry. I forgot doing my homework. May I hand it in this afternoon, Mr. Chen? said Li Ming.
李明说：对不起，我忘记做家庭作业了。我今天下午交好吗，陈老师?
3.have sth. done。(过去分词)(让别人)做某事
例如：I had my hair cut yesterday afternoon. 我昨天下午理了发。
My computer can not work now. I must have it repaired. 我的电脑有故障了，我必须让人修好它。
4. 感官动词后接不带to的不定式或者现在分词的区别
例如：see sb. do sth。看见某人(经常)做某事 和see sb. doing sth。看见某人(正在)做某事
I often see him do exercise in the morning. 我经常在早晨看见他锻炼身体。
When I was walking in the park, I saw him drawing a picture there. 当我在公园散步的时候，我看见他正在那里画画。
5. 在主动语态中，感官动词(see, hear, feel, watch等)和使役动词(make, have, let等)要求接不带to的不定式做宾语补足语，而在被动语态里，不定式要带上to。
例如：The boss often made the workers work 10 hours a day.
The workers were made to work 10 hours a day.
She was heard to use strong language. 听说她骂人了。