His hobby is playing football这里play为什么加ing

His hobby is playing football这里play为什么加ing 为什么Playing football.Play要加ing Tom likes playing football 这里play为什么要加ing 还有like为什么加S His hobby is playing baseball.其中,说明爱好为什么要加ing? Playing football is difficult.为什么用Play+ing , His hobby is ____(play) football my hobby is football.a,play b,plays c,playing He likes playing football very mucy ==play为什么加ING His hobby is playing football.(改一般疑问句) Do you like playing chess?为什么这里的play要加ing? do后面加动词原形那为什么是Do you like playing football?play为什么要加ing be动词am ia are 后面动词还要加ing吗?就是我们今天考试,His hobby is play volleyb