题干

下列说法正确的是(  )

A:电子邮箱中“cn”表示这个服务器是在中国注册的

B:激光频率单一、亮度高、平行度好、速度慢,常用于光纤通信

C:三颗同步通信卫星可以覆盖全部地球表面,实现全球通信

D:射频信号的频率比音频高比视频低

上一题 下一题 0.0难度 选择题 更新时间:2018-12-03 03:43:05

答案(点此获取答案解析)

A

同类题1

配对阅读。左栏是五个人物想要做的事。右栏是七个节目、地方和服务的简介。请为每个人选择最合适的节目、地方或服务。

 ____ Mrs. Smith wants to send her daughter to take some piano lessons during the coming summer holiday.

____ Sam and his girl friend want to spend the weekend to watch something new. They both like dancing.

____ Dannel wants to buy some newspaper to read so that he can improve his English. 

____ Miss Black wants to come to Beijing for the first time in August. She wants to enjoy the real Beijing Opera very much.

____ Tony and his colleagues will have a trip in Guangzhou next week. They need to rent a car and a driver who understands English. 

A.Watch Your Neck

This modern ballet is telling the story of “Dracula” which is the classic novel by Irish playwright Bram Stoker.

Time: 8:30 pm

February 2~9    Tel: 98558588

B.Children's Activity Center

Tel: 66589982

    Add: No.2 Zhongshan Road. (Singing lessons, piano lessons and dancing lessons. )

C.Art Show

A total of 10 artists living close to each other are jointly giving an art exhibition.

D.Peking Opera
Mei Lanfang's brave fighting against the Japanese during the war of Resistance against Japanese will open your mind.

E.Foreign Book Center

More and more increasing learning English books and newspapers, CDs. etc.

F.The Changcheng Hotel

Five star hotel. Looking for much experienced receptionists. Tel: (010)55883326 

G.Car-Hire Service

12 seat Forit transit van for hire in Zhujiang Business and Private Hire. We have English-speaking drivers.