2012英语四级语法讲义大全：非谓语动词三

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2、不定式的句法功能：
* S% i2 l$ J$ h5 d7 B1）作主语：
To finish the work in ten minutes is very hard.
1 y# n; i% _+ ~To lose your heart means failure.动词不定式短语作主语时，常用形式主语it作形式主语，例如上面两句可用如下形式：
It is very hard to finish the work in ten minutes.
7 K# h0 u2 t0 i4 EIt means failure to lose your heart.
2）作表语：
Her job is to clean the hall.
" W3 B; f$ f9 \" a/ w* KHe appears to have caught a cold.
3）作宾语：
常与不定式做宾语连用的动词有：want, hope, wish, offer, fail, plan, learn, pretend, refuse, manage, help, agree, promise, prefer, 如果不定式（宾语）后面有宾语补足语，则用it作形式宾语，真正的宾语（不定式）后置，放在宾语补足语后面，例如：
) @' N9 X3 X" o! G) nMarx found it important to study the situation in Russia.
动词不定式也可充当介词宾语，如：
4 e  t% L& ?3 ]) z5 UI have no choice but to stay here.
, A# M% l1 e/ N* K* `% cHe did nothing last Sunday but repair his bike.
- |% J* f& J. ]. N: }动词不定式前有时可与疑问词连用，如：
He gave us some advice on how to learn English.