stop------(from) doing sth. 阻止------做某事（主动句中from可省略，被动句中from不能省略）

prevent------(from) doing sth. 阻止------做某事（主动句中from可省略，被动句中from不能省略）

keep------from doing sth. 阻止------做某事（from不能省略）

eg:

1.You can't stop us (from) going if we want to .

2.No one can prevent him (from) drinking except docters .

3.I was prevented by illness from taking the exam .

4.The church bells keep me from sleeping .

5.The heavy rain kept us from going out .

6.The boss kept them from working in the rain .