非谓语动词是以动词的变化型(不定式,动名词和分词)来替代句子中成分, 可充当的成分有主语,宾语,定语,状语,补语等。
作主语: Walking is a good form of excise.
作宾语 I saw the birds singing.
作定语: Do you have something to eat?
作状语: The girl is only enough to be a waiter.
作补语: The coach had his players running all morning.