有关被动语态中的to
问题描述：
有关被动语态中的to
Our friends _____ playing football.
A.are seen B.seen C.are seen to D.seen to
我选的是C,但我们老师说答案是A,这里see 改为被动语态不是要加上to吗?
答
A
see sb do变为被动sb be seen to do
see sb doing 变为被动sb be seen doing