He ______ sing English songs.
问题描述：
He ______ sing English songs.
A.is often heard to B.is often heard C.often hears D.is often hering 选哪个?为什么?句子意思是?
答
A
sb be heard to do 这是被动的形式
(区别与hear sb do sth 这是主动的）
(hear感官动词用作被动语态中务必要加to)