—Are they about to have dinner？—Yes it in the dinning room.A. is servingB. is servedC. i

问题补充：

—Are they about to have dinner？

—Yes, it in the dinning room.

A. is serving

B. is served

C. is being served

D. serve

答案：

A. is serving

B. is served

(答案→)C. is being served

D. serve

解析：考查时态。句意：—他们要开饭了吗？—恩，在客厅正在开饭。Dinner与serve（服务）构成被动关系。故C正确。