问题描述：
The missing boys were last seen ____ near the river.(NMET94 25)
A.playing B.to be playing C.play D.to play
我觉得选b 因为感官动词see变为被动时要加to,然后又强调正在,所以选b
A.playing B.to be playing C.play D.to play
我觉得选b 因为感官动词see变为被动时要加to,然后又强调正在,所以选b
问题解答：
我来补答展开全文阅读