He is running这句话为什么run要加ning

He is running这句话为什么run要加ning time is running out 为什么run要加ing呢? 跑不怎么样为什么说是 what about running 为什么要加ing?而不是 what about run? Bill is a great running star.He is very well.中,running为什么要用r run的现在分词running前面要加be吗? The cat is running with a mouse .这句话中with用的对吗 run with 鼓励；与… He likes running,he ________fast.( run,runs) 请问这句话怎么译?He is running his second Race in as many years does he spend an hour running to school every morning run为什么 英语正在进行时用法为什么加ing时又是不一样 比如run- running clean- cleaning. He is s____about running? he is running