被置换的设备、管道在置换作业完毕后必须与系统进行（）。
A、有效隔离
B、简单隔离
C、可靠隔绝
参考答案：C
Woman: Professor Smith, I really need the credits to graduate this summer.Man: Here in this school: the credits are earned, not given.Question: What do we learn from the conversation
A．The woman has to attend a summer course to graduate.
B．The man thinks the woman can earn the credits.
C．The woman is begging the man to let her pass the exam.
D．The woman is going to graduate from summer school.
挤压式（）接头适用于中、低压管道，如室内热水采暖、给水、热水、燃气管道。
A.法兰
B.螺纹
C.卡套管
D.焊接
