—Can those at the back of the classroom hear me?—No problem.A. seatB. sitC. seatedD. sat

问题补充：

—Can those at the back of the classroom hear me?

—No problem.

A. seat

B. sit

C. seated

D. sat

答案：

A. seat

B. sit

(答案→)C. seated

D. sat

解析：“sit”为不及物动词，可用“sitting”作定语；“seat”为及物动词，常与反身代词连用或用“be seated”形式。