we did a survey of what movies students like watching为什么like不加ed

问题描述:

we did a survey of what movies students like watching为什么like不加ed

we did a survey这是过去的动作,所以,用过去式加以强调/表明.
但所调查的内容.what moviesthe students like watching.
如果用过去时,就是说:"过去"学生们喜欢看的,
但明显不是这个意思.所以不用加.