四六级考试

【单选题】
A、Microwaves are strange electric waves.
B．Microwaves travel in straight lines and do not follow the curve of the earth’s surface.
C．There are not any wires to send microwaves.
D．We must amplify microwaves in relay stations.

网考网参考答案：B
网考网解析：
[听力原文] Why do we have to send radio waves from one relay station to another document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>