1.作定语：
分词词组作定语相当于一个定语从句，而不定式作定语不可以变为定语从句，并且它所修饰的词不为逻辑主语；动名词作定语表示所修饰的词的类别或用途。
They found a place to live in.
The worker who retired last week is a model worker. = The worker retiring last week is a model worker.
2.作表语：现在分词作表语表示主语本身所具有的特征
过去分词作表语表示外界给主语创成的特征
不宜作表语的情况：a.表将来 b.表示按法律法规，规章制度必须做或禁止做的事，动名词作表语可以与主语互换而不影响句子的原意。
The crowed is exited.
The story is moving.
The glass is broken.
All I could do is (to) go back home.
His hobby is collecting stamps.
He is collecting stamps.
3.作补语：现在分词作补语表示与宾语的关系是主动的，并表示正在发生动作。
过去分词作补语表示与宾语的关系是被动的。
不定式作补语往往是一些固定动词搭配。
ask sb. to do sth. advise sb. to do sth.
They considered the problem settled.
We hear them singing at the next door.
They asked me to fetch some papers.
注：a.一些使役动词 make 、have、let、get、keep的用法:
b.一些感官动词 see、hear、notice、feel的用法:
c. with结构的用法
with+名词+介词短语
with+名词+形容词 with his hands empty
with+名词+doing
with+名词+done
with+名词+to do
4.作状语：分词词组可以充当时间、原因、目的、结果、让步、条件，伴随情况状语，
Because he was beaten black and blue, he didn't come to attend the meeting.
Beaten black and blue he didn't come to attend the meeting.
After he had finished his homework, he went out for a walk.
Having finished his homework he went out for a walk.
Because he was a manager, he had to do more things than the others.
Being a manager he had to do more things than the others.
If the weather permits, we will go for a picnic.
Weather permitting we will go for a picnic.
Because he has been watched all the time, he must be a spy.
having been watched all the time he must be a spy.
Since there was a lot of water on the floor, we couldn't go out.
There being a lot of water on the floor we couldn't go out.