1．在it’s no use, it’s not much use, it’s no good后要求用动词＋-ing。但是在it is of no use后则要用动词不定式。： It’s no use crying about it. You must do something. It’s no good writing to him; he never answers letters. It’s of no use to cry over spilt milk. 2．在有些动词后面既可以跟动词＋-ing，也可以跟动词不定式，这类动词有：
在有些动词后面，两种结构之间的意义差别不大。例如： He prefers writing (to write) an outline before he writes a summary. He had really intended staying (to stay) longer. 但在某些动词之后，两种结构之间的意义差别较明显。
