接地体的连接应采用搭接焊,其扁钢的搭接长度应为()。
A、扁钢宽度的3倍并三面焊接
B、扁钢宽度的3倍
C、扁钢宽度的2.5倍
D、扁钢宽度的2倍并三面焊接
参考答案:D
Although it is _____ to watch programs on TV sometimes, I think people shouldn’t spend all the time watching it.
A.worthwhile
B.worthy
C.worth
D.worthy of
光缆的光束是在()内传输
A、玻璃纤维
B、透明橡胶
C、同轴电缆
D、网卡