问题 单项选择题

对于居民小区的WLAN建设,以下说法不正确的有()

A、覆盖半径在40米以内,需保证天线入口功率控制在22dBm左右,天线与AP之间需根据需要合理放置天线的位置,AP与天线之间线缆尽量不要超过80米

B、局域网交换机和AP之间网线距离要求低于70米

C、由于居民区内楼宇宽度和距离不同,为了保证楼宇的覆盖,需要进行天线的选择,保证需要覆盖的区域处于天线的覆盖范围以内,并且还要有效控制信号泄漏

D、优选在楼外立面或楼顶安装定向天线,对对面楼层进行覆盖的方式

答案

参考答案:A

阅读理解

On Saturday nights, A.J.Coston doesn’t get a lot of sleep. Usually three or four times a night, a loud bell rings, a red light flashes, and he has to jump out of his bed. That’s because he’s a weekend volunteer firefighter(消防员)with Loudoun County Fire and Rescue Station 13 in Northern Virginia. During the week, he lives at home with his mom, dad and sister and does his main job which is going to high school.

“I have always wanted to get into firefighting since I was a little kid watching fire trucks go by,” he says. “One day on the Internet I noticed that Loudoun County offered a junior firefighter program.” He was only 16, but he got it.

Fighting fires is dangerous work. Firefighters never stop practicing the skills they need to stay safe. Once Coston learned those skills, he was allowed to work inside burning buildings.

“Teamwork is most important,” he says. “It’s the whole team that puts the fire out.”

Firefighters feel great about helping people. “My most unbelievable call was probably the time four kids were struck by lightning,” says Coston. He will be off to college next fall, building on his dream job. “I’ll get my degree in emergency(紧急情况) medical care. and then work in a fire and rescue company for a while. I want to be a flight doctor on a helicopter in the end, but I will never forget the days as a firefighter. These are my unforgettable experiences,” he says.

小题1: Coston can’t sleep well on Saturday nights because _____.

A.he has to work part-time at weekends

B.he has some sleeping problems

C.he has to do his job as a volunteer firefighter

D.he always worries that there may be a fire小题2:What do we learn about Coston from the passage?

A.He doesn’t like studying at school.

B.He will go to college next year.

C.He dreams to be a great hero one day.

D.He is only sixteen years old.小题3:In Coston’s opinion, what is the key thing in putting out a fire?

A.Skills.

B.Teamwork.

C.Courage.

D.Equipment.小题4:All of the following are true EXPECT that _____.

A.Coston wanted to be a firefighter when he was a kid

B.Coston tried several times before he became a volunteer firefighter

C.firefighters feel proud that they can help people

D.firefighters have to practice skills all the time to stay safe

单项选择题