一般活动连接器的平均接头损耗值是()
A.0.5dB
B.0.3dB
C.0.2dB
D.0.1dB
参考答案:A
先秦道家的主要著作有()。
A.《道德经》
B.《论语》
C.《庄子》
D.《管子》
The two astronauts () someday hope it is to fly the craft into earth orbit were flight testing.
A. that
B. whom
C. whose
D. who