. My pain ___________ obvious the moment I walked into the room, for the first man I met  asked me pitifully:" Are you feeling all right?"

A．must be

B．must have been

C．could be

D．could have been

对运行中的压力容器进行检查，主要是对（）、（）、（）及操作人员等方面的检查，及时发现问题，迅速处理，保证容器安全运行。