The boy was last seen near the gate of the park.A. missed playingB. missing playC. los

问题补充：

The boy was last seen near the gate of the park.

A. missed, playing

B. missing, play

C. losing, to be playing

D. lost, playing

答案：

A. missed, playing

B. missing, play

C. losing, to be playing

(答案→)D. lost, playing

解析：句意：失踪的小男孩最后一次被看见是在公园的门口。失踪的小男孩可以用the missing boy或the lost boy；这里是短语see sb doing它的被动式是sb be seen doing，故选D。