反映瓦斯抽放效果的指标（）。
A、钻孔瓦斯流量衰减系数
B、百米钻孔瓦斯涌出量
C、瓦斯抽放量
D、煤层透气性指标
参考答案：C
The teacher asked the girl again, raising his voice a bit, but still _____ no answer.
A. receiving
B. received
C. receive
D. to receive
连花清瘟成分由：连翘、（）、炙麻黄、炒杏仁、大黄、红景天等13味中药组成。
