问题 单项选择题 案例分析题

某单回路500kV架空送电线路,采用4分裂LGJ-400/35导线。导线的基本参数见表。

注:拉断力为试验保证拉断力。该线路的主要气象条件为:最高温度40℃,最低温度-20℃,年平均气温15℃,最大风速30m/s(同时气温-5℃),最大覆冰厚度10mm(同时气温-5℃,同时风速10m/s。且重力加速度取10)。

若代表档距为500m,年平均气温条件下的应力为50N/mm2时,最高气温时的应力最接近下列哪项数值()?

A.58.5N/mm2

B.47.4N/mm2

C.50.1N/mm2

D.51.4N/mm2

答案

参考答案:B

填空题
阅读理解

Have you felt annoyed when a cellphone rings during the class? Something must be done to stop this.Now in New York City, USA,a rule is carried out in schools.Students can’t even bring cellphones to schoo1.Is it a good thing or not?

Anxious parents say that cellphones are an important tool in holding New York city’s families together.

“I worry about it,” said Elizabeth Lorris Ritter, a mother of a middle school kid. It’s necessary in our everyday life.We have a washing machine. We have running water, and We have cellphones.”

Many American parents think cellphones connect them to their children on buses,getting out from subways, walking through unknown places.

“I have her call me when she gets out of school,”said Lindsay Walt, a schoolgirl’s mother. “No one in New York is going to let their child go to school without a cellphone”

What about the cellphone owners, the students? Most of the students said cellphones were essential and the cellphone was like all extra(额外的)hand or foot for them.

“I feel so empty,”said May Chom,1 4.There is also no way to listen to music on the way to school without my phone.It will be a really, really boring trip.”

小题1:You can use a cellphone___________.

A.to enjoy listening to music

B.to work as running water

C.to work as a washing machine

D.to send children to school小题2:Which of the following statements is TRUE?

A. Many American parents don’t think cellphones are necessary for the students.

B.Cellphones only bring troubles to the school life.

C. Cellphones connect children with their families when they are outside.

D. All the school children agreed not to use cellphones at school.小题3:What does the underlined word “essential” mean in Chinese?

A.时髦的.

B.必要的.

C.昂贵的.

D.浪费的小题4:The article is about the____ in carrying out the rule not to use a cellphone in schoo1.

A.happiness

B.interest

C.problem

D.satisfaction