He watched a group of children ________ (play)football on the playground

问题描述:

He watched a group of children ________ (play)football on the playground
A.to play B.play C.played

playing
watch sb.doing sth.看某人正在做某事
那就:play
watch sb.do sth.看某人做某事A. to play B.playC. played没有playingB 理由见上面C.为什么不对watch 后跟动词原形啊,不要过去式啊