The girls______a game called Bomb happily when the teacher suddenly entered the classroom.

A．played

B．were playing

C．are playing

D．had played

搜救雷达应答器内的电池要求在待命状态和应答状态的工作小时（）。

A、48小时

B、24小时

C、96小时，8小时

D、96小时，48小时