________ us calmly together, our captain made an announcement__________ we must save essential supplies before the day broke.

A．Calling; that

B．To call; that

C．Calling; which

D．To call; which

一般用来测量气体质量流量的流量计是（）。

（A）热式质量流量计

（B）涡街流量计

（C）超声波流量计

（D）转子流量计