在更换传输设备的单板时，以下说法正确的是（）
A、可以不佩带防静电手环
B、必须佩带防静电手环
C、先用手摸以下机柜门即可
参考答案：B
______ full preparations, they decided to put their wedding off until December. [ ]
A. They did not make
B. having not made
C. They had not made
D. Not having made
A．The advanced equipment in the laboratory.
B．The so-early start-working hour.
C．The terrible working habit of his colleagues.
D．The interval between the start-working hours of two places.
