不定式在某些形容词之后.且与主语有动宾关系.常见形容词有:hard,defficult,easy,heavy,fit,good,comfortable,convenient,impossible等.例如:The problem is easy to do./The question is difficult to answer./The box is heavy to carry./The project is impossible to complete in a year.比较:The problem is to be done./The question is to be answered.没有形容词时.虽然不定式与主语是动宾关系.但必须用被动式. 【查看更多】
