现在分词是ing形式吗

只能是动名词的情况作主语——主语只能是一个名词性的概念，动词不定式，主语从句都可以做主语

例：Eating too much is bad for your health.

特别说明：动名词作主语谓语动词是单数!

作表语，可转换成主语

例：Her favorite sport is skating. =Skating is her favorite sport.

特别说明：不定式和动名词均可用作主语和表语有区别

区别是：动名词多指笼统的、抽象的概念，而不定式则多指具体的、一次性的动作。

作宾语，放在动词或介词之后

例：She likes singing and dancing.

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