论证报告应( )，由专家组组长签字，并附每位专家的论证意见。 A．准确 B．全面

飞鸟号最新发现：宇宙x射线源首次观测成功．日本文部省宇宙科学研究所最近宣布了一项发现．他们利用飞鸟号x射线天文卫星在世界上首次成功地观测到了银河外x射线源．科研小组认为，此种x射线是从遥远的星系中心酷似黑洞的地方放出来的，大约经过了100亿年才到达我们所在的银河系．宇宙科学研究所的专家利用飞鸟号x射线望远镜，对室女座、后发座、天蝎座等之外的星系进行了观测，所用的x射线望远镜的灵敏度比以前的望远镜高出百倍以上．科研小组对观测到的x射线进行了分析，特别是那些短波长的x射线，结果表明宇宙x射线是距我们所在银河系几十亿乃至百亿光年的天体里放射出来的．这种天体有近百个之多，有的质量相当于太阳的1亿倍．这些天体都与附近天体组成一个中心存在黑洞的星系，x射线就是从黑洞中放出来的．外星系每l*

这次飞鸟号观测到银河系外x射线源的意义在于()

A．为弄清宇宙及星系黑洞的诞生提供了重要线索

B．为弄清太阳系的形成提供了重要线索

C．为弄清银河系的形成提供了重要线索

D．为弄清人类的起源提供了重要线索

Melissa Poe was 9 years old when she began a campaign for a cleaner environment by writing a letter to the then President Bush. Through her on efforts, her letter was reproduced on over 250 donated billboards (广告牌)across the country.

The response to her request for help was so huge that Poe established Kids For A Cleaner Environment (Kids F.A.C.E.) in 1989. There are now 300,000 members of Kids F.A.C.E. worldwide and it is the world’s largest youth environmental organization.

Poe has also asked the National Park Service to carry out a “Children’s Forest” project in every national park. In 1992, she was invited one of only six children in the world to speak at the Earth Summit in Brazil as part of the Voices of the future Program. In 1993, she was given a Caring Award for her efforts by the Caring Institute.

Since the organization started, Kids F.A.C.E. members have distributed and planted over 1 million trees! Ongoing tree-planting projects include Kids’ Yards — the creation of backyard wildlife habitats (栖息地) and now Kids F.A.C.E. is involved in the exciting Odyssey, which is a great way to start helping.

“We try to tell kids that it’s not OK to be lazy,” she explains, “You need to start being a response, environmentally friendly person now, right now, before you become a resource-sucking adult.”

72. Kids F.A.C.E. is __________.

A. a program to help students with writing

B. a project of litter recycling

C. a campaign launched by President Bush

D. a club of environmental protection

73. What can we learn about Poe?

A. She was awarded a prize in Brazil.

B. She donated billboards across the country.

C. She got positive responses for her efforts.

D. She joined the National Park Service.

74. Kid’s Yards is ____________.

A. established in national park

B. started to protect wildlife

C. a wildlife-raising project

D. an environment park for kids

75. Which of the following can be inferred from the text?

A. Adults are resources –sucking people.

B. Poe sought help from a youth organization

C. Kids F.A.C.E. members are from the U.S.

D. Kids are urged to save natural resources.

以下关于虚拟局域网组网方祛的描述中，错误的是______。

A．用交换机端口号定义虚拟局域网

B．用MAC地址定义虚拟局域网

C．用传输层地址定义虚拟局域网

D．基于IP广播组的虚拟局域网

承租人不交房租，出租人该怎么讨租呢？

木门是由那些部分组成（）。

A.门框

B.门扇

C.都对

D.都不对