great fun it is to have a cold drink on a hot day!

A．How

B．How a

C．What

D．What a

压力释放阀根据释放阀（）选择安装法兰盘，安装时，压力释放阀底部密封圈与法兰盘光面对接。

A.材质

B.型号

C.大小

D.位置