8.1 stop doing/to do
stop to do 停止，中断做某事后去做另一件事。
stop doing 停止做某事。
They stop to smoke a cigarette. 他们停下来，抽了根烟。
I must stop smoking.. 我必须戒烟了。
She reached the top of the hill and stopped ___ on a big rock by the side of the path.
A. to have rested B. resting C. to rest D. rest
答案：C。由题意可知，她到了山顶，停下来在一个路边的大石头上休息。因此，应选择"stop to do sth. 停下来去做另一件事"。而不仅仅是爬山动作的终止，所以stop doing sth.不正确。
8.2 forget doing/to do
forget to do 忘记要去做某事?！?未做)
forget doing 忘记做过某事?！ ?已做)
The light in the office is stil on. He forgot to turn it off.
He forgot turning the light off.
他忘记他已经关了灯了?！ ?( 已做过关灯的动作)
Don't forget to come tomorrow.
别忘了明天来?！ ?(to come动作未做)
---- The light in the office is still on.
---- Oh，I forgot___.
A. turning it off B. turn it off C. to turn it off D. having turned it off
答案：C。由the light is still on 可知灯亮着，即关灯的动作没有发生，因此用forget to do sth.
而forget doing sth表示灯已经关上了，而自己忘记了这一事实。此处不符合题意。
8.3 remember doing/to do
remember to do 记得去做某事 (未做)
remember doing 记得做过某事 (已做)
Remember to go to the post office after school.
Don't you remember seeing the man before?
8.4 regret doing/to do
regret to do 对要做的事遗憾?！ ?未做)
regret doing 对做过的事遗憾、后悔?！ ?已做)
I regret to have to do this, but I have no choice.
I don't regret telling her what I thought.
---You were brave enough to raise objections at the meeting.
---Well, now I regret ___ that.
A. to do B. to be doing C. to have done D. having done
答案：D。regret having done sth. 对已发生的事感到遗憾。regret to do sth. 对将要做的事感到遗憾。本题为对已说的话感到后悔，因此选D。
8.5 cease doing/to do
cease to do 长时间，甚至永远停做某事。
cease doing 短时停止做某事，以后还会接着做。
That department has ceased to exist forever.
The girls ceased chatting for a moment when their teacher passed by.
8.6 try doing/to do
try to do 努力，企图做某事。
try doing 试验，试着做某事。
You must try to be more careful.
I tried gardening but didn't succeed.
8.7 go on doing/to do
go on to do 做了一件事后，接着做另一件事。
go on doing 继续做原来做的事。
After he had finished his maths，he went on to do his physics.
Go on doing the other exercise after you have finished this one.
8.8 be afraid doing/to do
be afraid to do 不敢，胆怯去做某事，是主观上的原因不去做，意为"怕";
be afraid of doing 担心出现doing的状况、结果。 doing 是客观上造成的，意为"生怕，恐怕"。
She was afraid to step further in grass because she was afraid of being bitten by a snake.
She was afraid to wake her husband.
She was afraid of waking her husband.
8.9 be interested doing/to do
interested to do 对做某事感兴趣，想了解某事。
interested in doing 对某种想法感兴趣，doing 通常为想法。
I shall be interested to know what happens.
I'm interested in working in Switzerland. Do you have any idea about that?
8.10 mean to doing/to do
mean to do 打算、想
mean doing 意味着
I mean to go, but my father would not allow me to.
To raise wage means increasing purchasing power.
8.11 begin(start) doing/to do
begin / start to do sth
begin / start doing sth.
How old were you when you first started playing the piano?
2) begin, start用进行时时，后面动词用不定式to do
I was beginning to get angry。
3) 在attempt, intend, begin, start 后接know, understand, realize这类动词时，常用不定式to do。
I begin to understand the truth。
It began to melt.
8.12 感官动词 + doing/to do
感官动词 see, watch, observe, notice, look at, hear, listen to, smell, taste, feel + do 表示动作的完整性，真实性;+doing 表示动作的连续性，进行性
I saw him work in the garden yesterday.
I saw him working in the garden yesterday.(强调"我见他正干活"这个动作)
1)They knew her very well. They had seen her ___ up from childhood.
A. grow B. grew C. was growing D. to grow
答案：A。因题意为，他们看着她长大，因此强调的是成长的过程，而非正在长的动作，因此用see sb do sth 的句型。
2)The missing boy was last seen ___ near the river.
A. playing B. to be playing C. play D. to play
答案A. 本题强调其动作，正在河边玩，应此用see sb. doing sth句型。