The prices have been rising all the time, especially that of housing. So it is high time the government _______ action to solve it.

A．takes

B．have taken

C．took

D．to take

法兰的公称压力并不代表它的允许工作压力，这两个压力之间的差别完全取决于（）。

A．法兰材料

B．工作温度

C．法兰形式

D．工作介质