请教一道英语语法题,为什么The parents watched the children _________ their invention.A.demonstrating B.demonstrate C.to demonstrate D.demonstrated
问题描述：
请教一道英语语法题,为什么
The parents watched the children _________ their invention.
A.demonstrating B.demonstrate C.to demonstrate D.demonstrated
答
现在完成进行时表示的是动作的持续,不可能是一直在交（从过去交到现在）,所以不能选c.A对