不定式的用法 不定式是动词的一种非谓语形式,它一般由虚词(或称不定式符号)to 作为标记,如 to study, to work 等,但在某些情况下也可以不带 to
不定式可以有自己的宾语或状语
带有宾语或状语的不定式叫不定式短语
下面具体谈谈动词不定式的用法
(一)动词不定式作主语 动词不定式作主语一定要带 to,谓语动词用单数
如: To answer this question is easy
为了避免句子“头重脚轻”,英语中往往用 it 代替不定式,作先行主语(形式主语),将动词不定式后置
如: To study foreign languages is very important
It is very important to study foreign languages
作形式主语的 it 只是一个引导词,没有具体意义
it 在以下句型中也用作形式主语: It takes (sb) + 时间词+不定式+其它,意为“花费(某人)多少时间做某事”
如: It took her three years to learn Chinese
It will take me two hours to finish my homework
How long did it take you to get there
注意:当动词不定式作主语时,如果是疑问句,通常用 it 作形式主语
如: Does it cost you a lot of money to collect stamps
(二)不定式作表语 不定式用于 be 动词后作表语
如: My wish is to become a scientist
注意:不定式作表语,to 常省略
如: All I did was (to) press the button
(三)不定式作宾语 不是所有的动词后面