问题 单项选择题

根据《通信电源设备安装工程设计规范》,对于采用电源馈线的规格,下列要求中错误的是()。

A.通信用交流中性线应采用与相线相等截面的导线

B.线路的电压损失应满足用电设备正常工作及起动时端电压的要求

C.接地导线及机房内导线应采用铜芯导线

D.沿海等有盐雾腐蚀的环境条件下,应采用铜芯导线

答案

参考答案:C

阅读理解

阅读理解。

     Houston, Texas (June 8, 2002)-In 2004, the National Aeronautics and Space Administration (NASA)

will send two robots (机器人) to separate places of Mars to seek out past or present signs of water. It is

all exciting idea to send two robots driving over very different places of Mars at the same time, to be able

to see what is on the other side of the hill.

     Last month, NASA announced it was sending one robot to Mars, but after two weeks, it decided there

was enough money for two.

     The robots will be sent up within two weeks of each other in May and June of 2003 from Kennedy

Space Center. If all goes well, the two spacecraft (宇宙飞船) will touch down on Mars,after a

seven-and-a-half-month space flight,on January 2 and 2O, 2OO4 The robots, each weighing 150 kilograms,

can cover 100 meters per day. They are designed to be able to examine the mineral content of the soil, and

their special camera will take pictures of the lands and hills Although they will be under control from Earth,

the robot, are able to move more freely compared to those sent up before them.

     The actual landing points have not been determined yet, but the scientists say it will be in areas where

they hope to find water.

1. According to the news report, scientists plan to send robots up to Mars to ______.

A. find out whether there is water on Mars

B. see if robots can find minerals there

C. test how fast robots can drive there

D. prove that robots can work on Mars

2. How long in between will the two robots be sent to Mars?

A. 1 year

B. 7.5 months.

C. 2 months.

D. 2 weeks.

3. One of the important jobs for the robots on Mars is to ______.

A. study the soil

B. walk everywhere

C. test the new camera

D. find a suitable landing point

4. We can infer from the last sentence that scientists ______.

A. have changed the landing points many times

B. hope to land the robots on the surface of water

C. are still working on the plan

D. know where they can find water

单项选择题