I find that playing football is interesting .为什么用playing?不能用

I find that playing football is interesting .为什么用playing?不能用 playing football sound interesting Playing football is interesting He is playing football 怎样分主谓 he is playing football用playing football提问 playing computer games is very interesting 为什么用is Playing fottball is interesting To play football is inteerss Playing football and climbing ___ interesting.is 还是 are sport is interesting an football playing 怎样连词成句 Playing football is difficult.为什么用Play+ing , --Jim is playing football. I am（）.playing football playing the football play football I saw that he was playing football同义句