更换法兰阀门时，打开旁通阀，关闭下流阀门后再关闭上流阀门，倒通流程。
参考答案：错
They had a pleasant chat _______ a cup of coffee. [ ]
A. for
B. with
C. during
D. over
断路器交接试验，每一个气室年漏气率不应大于（）%。
A.0.5
B.1.0
C.1.5
D.2.0
