swim为什么变成swimming?

swim为什么变成swimming? swim 为什么这在进行时 变成swimming? My father helps me with swimming.为什么这时候swim要变成swimming? went swimming 为什么swim要加ing swim team为什么不是swimming clud? go swim还是go swimming 为什么 swimming is my favorite.为什么不是swim swimming lesson为什么swim要加ing go together for swimming还是swim .为什么? swim------swimming, do you enjoy swimming? swim 既是动词也是名词那swimming为什么不能改为swim 为什么用swimming star 而不用 swim star