四级语法辅导：动词不定式的用法

文章作者 100test 发表时间 2007:02:25 18:06:36
来源 100Test.Com百考试题网

不定式是历次大学英语四级考试必考的内容。不定式在句子中可做主语、宾语、表语、定语、状语和宾语补语。

1)不定式做主语一般表示具体的某次动作。
【例如】
To complete the 30storied building in one year was quite a difficult task.
To do that implies taking responsibility.
当主语较长，谓语较短时，常用it做形式主语，而将不定式放到谓语的后面。

【例如】
It is important for modern young people to master at least two foreign languages.
It做形式主语，不定式放在谓语动词之后常用于下列结构中：
a) It is＋形容词(easy, important, difficult, foolish, inconvenient, unnecessary, right, wrong...)＋( for/of sb.)＋不定式

【例如】
It is essential to reserve a table in advance of Christmas Eve.
It is hard to put my hopessintoswords.
It is not easy to catch fish with your hands only.
It is important for us young people to learn English and master it.

b) It is＋名词(a pleasure, a pity, a pleasant thing, one’s duty, an honor, a shame, a crime, no easy job...)＋不定式

It is a sheer waste of time to read that kind of trash.
It is a pity to have to go without her.
It is a glorious death to die for the people.

c) It takes (sb.) some time (hours, months, days, a lot of time, patience...)＋不定式

It takes me three hours to learn English each day.
It took them half the night to get home in the snow.

2)不定式作表语不定式作表语常表示将来的动作，主语常常是表示意向、打算、计划的词，如wish, idea, task, purpose, duty, job等。

【例如】
The most important thing for one’s health is to have plenty of exercise.
My chief purpose has been to point out the difficulties of the matter.