金属电缆桥架及其支架全长应不少于()处与接地(PE)或接零(PEN)干线相连接。
A.1
B.2
C.3
D.4
参考答案:B
Tom______half an hour doing his homework and listening to pop music ______him 20 minutes.
A.costs; spends
B.spends; take
C.takes; costs
D.spends; takes
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