I.词语辨析：

1、possible / probable / likely

possible：指客观上有可能性，但含有希望很小的意思；不能用人做主语。常用句式：

It is possible to do sth. / It is possible for sb. to do sth. / make it possible for sb. to do sth.

另外：名词前有：all, every, the only, the best 及其它形容词的最高级修饰时，possible一般放于名词之后，作后置定语, 但也可以放于名词前。

e.g. This is the only way possible.

They have tried every possible method to do the experiment.

probable：probable比possible可能性大，"很有可能、大概"，所以我们可以这样说："Probable is more possible than possible"。 probable 指有实际的依据和逻辑上的合理性；

probable 也不用人做主语。常用句式：It is probable that .....

e.g. It is probable that he will be late again.

It seems probable that he will come.

Such a thing is possible, but not probable.

likely：表示从外表迹象进行判断有可能发生的事。常用以下句型：

　　Sb. is likely to do sth. / It is likely that sb. will do sth. / Most(Very) likely sb. will do sth.

　　 e.g She is likely to go to the USA soon.

　　 It is likely that we'll have another test.

　　 Very likely it will rain in no time.

2、separate / divide

separate：指"把因某种原因而混在一起的人或物分开"。

e.g. I tried my best to separate the two fighting boys, but failed.

Please separate these papers in half an hour.

常用句式：separate A from B

e.g. Can you separate good apples from the bad ones for me?

His whole family were separated from one another during the war.

divide：指"把原为一体的整体分割开来，成为若干个小的个体"。常用句式：

divide A into B：把A分成B.

e.g. He divided the cake into four parts and gave each of us one.

divide sth. between / among sb.：和某人分享/分担某物/事

e.g. We divide the rent among the three of us.

3、prevent / protect

prevent：阻止、防止（事情的发生）。与from连用，from可省略。

e.g. The heavy rain prevented us（from）going to school.

Nothing will prevent history（from）going forward.

含有"阻止、防止某人干某事"意思的词组还有：

stop ... (from) doing sth. = keep ... from doing，在keep...from中，from不能省。

e.g. His illness stopped him (from) going to Kunming on business.

His fear of darkness keeps him from going out at night.

protect：保护，常用句式：protect sb. / sth. from ....：保护