承压容器的安全附件中，属于安全泄压装置的有（）。
A.压力表
B.爆破片
C.安全阀
D.易熔塞
E.超温报警和连锁保护装置
参考答案：B, C, D
.
As reported in the essay by Prof. Brown, it is only in the most difficult circumstances ________ a man’s abilities are fully tested.
A．when
B．where
C．that
D．as
简述单式筒子架与复式筒子架的区别。
