产生声影的可能性最小的是
A．骨质界面
B．胆结石
C．含气的肺
D．手术钢夹
E．气体界面
参考答案：D
— Do you mind my opening the door?
— _____. It's too hot in the room. [ ]
A. Yes, I do
B. Certainly
C. Sure, I will
D. Of course not
