1、作谓语的时候，动词加ing前面必须加上be动词，形成be+动词ing(现在分词)作句子谓语，构成进行时态句子。

如：He is reading a book now.他正在看书.2、动词作介词的宾语要加ing(动名词)。如：I'm looking forward to seeing you again.我期盼着再次见到你.3、部分动词用动词做宾语。做宾语的动词要加ing(动名词)。如：I have finished reading three books.我已经看完三本书.4、一些固定句式后面要加动词ing(现在分词)。如：We have fun Playing in the park on Sunday.星期天我们在公园玩得很开心。

5、动词修饰名词做后置定语时，要加ing(现在分成)如：I felt something moving in the house.我感觉房子里有东西在动。扩展资料动词可分为三类分别是：单字词（One-Word Verb）、短语动词（Phrasal Verb）、动词短语（Verbal Phrase）例如：The English language contains many phrasal verbs and verbal phrases.英语里有许多短语动词和动词短语。（contains是单字动词。）Students should learn to look up new words in dictionaries.学生们学会查字典。（look up是短语动词。）The young ought to take care of the old.年轻人应照料老人。（take care of是动词短语。）