收端局要主叫号码,则它应发:()A.ANC B.GRQ C.CBK D.IAI 发布时间:2017-10-08 15:04 │ 来源:www.tikuol.com 题型:单项选择题 问题: 收端局要主叫号码,则它应发:()A.ANCB.GRQC.CBKD.IAI
题型:单项选择题 关于声波和电磁波,下列说法中正确的是( )A.它们都能产生反射、折射、干涉、衍射等现象B.它们都需要介质才能传播C.由一种介质进入另一种介质时,它们的频率会改变D.由空气进入另一种介质时,它们的波速和波长都变小 查看答案
题型:单项选择题 The book, ____ are true stories about great scientists of the 20th century, is well worth reading. [ ]A. which B. what C. in which D. of which 查看答案