下载APP
举一反三
【单选题】电波的衰落现象是指( )。
A.
信号随时间或大或小的起伏变化
B.
信号随传播距离的增大而减弱的现象
C.
发射信号随发射功率的变化而变化
D.
接收功率随时间变化而变化
【单选题】Passage 2The young people who talk of the village as being “dead” are talking nothing but nonsense, as in their hearts they must surely know. No, the village is not dead. There is more life in it now ...
A.
there is no end to the talking about....
B.
It is harmful to talk about….
C.
It is not meaningless to talk about....
D.
there is no reason for talking about