低频25.7HZ的定义是什么?
参考答案:
载频切换信息码。
— There ________a football match on TV tonight. I can’t wait to watch it.
— Me, too. It’s ________ Guangzhou Evergrande and the Australian team Melbourne Victory.
A.will be; between
B.will be; both
C.will have; between
D.will have; both
线间距小于()m时,禁止在正线与邻线间行走。
A.3.5
B.4.5
C.5.5
D.6.5