问题 单项选择题

核电站的一次性投资确实比火电站大一些。衡量电站的经济价值,还要核算电站运行后消耗的燃料、设备折旧、()、运行管理等费用。30年来,国际上对煤电成本与核电成本所作的等值比较,显示出修火电站实际出现的低投入经济效应的负走向,修建核电站则正相反。目前,已有几十个国家建成300余座核电站,总功率达2亿千瓦左右,绝大多数核电站已使核电成本降至煤电的60%左右。现代经济价值观取得了又一次胜利

至于核电站所出现的事故,不足以否定其安全性。从核反应形式看,原子弹可以和核电站类比,但原子弹所用的铀-225浓度在弹体中高达90%,因此造成核链式反应的不可控性;而核电站采用的燃料是浓度低于4%.的铀-235,这样反应效应就与原子弹有了根本的区别。从实际情况看,任何形式的电站,只要设计管理出了问题,都可能导致事故发生。1979年印度一座大坝水电站爆炸竟使1.5万人丧生,当然这不是说切尔诺贝利核电让核物质外泄夺走了人的生命就值得庆幸。值得庆幸的是核电站系统工程技术有了新突破,核电站安全保险系数优于火电站。说到环境保护,最先进的火电站也难以让人作乐观的承诺,而核电站则别具优势。

根据题意,准确概括核电站特点的一组是()。

①高投入高质量低消耗

②经济价值高于火电站

③使用寿命高于火电站

④每度核电成本仅仅相当煤电的60%左右

⑤安全性强有利于保护环境

A.①③

B.②③⑤

C.②⑤

D.①④

答案

参考答案:C

单项选择题
阅读理解

阅读表达。

     Long ago, children played like children do today. They got dirty from running around. Older people got

dirty from working all day. But then there was no soap. What did people do to get clean?

     At first, people just went into a lake. They washed in the water. But then learned to use other things with

the water. They put plants in a fire until they turned black. In this way,they made ashes. People used the ashes

like soap. They also used oil like soap. But these were not very good.

     The first soaps were hard to make. First water was put in a pot. Then fat was added. Oil and ash were

mixed in the pot, too. Then it was put on a fire. Everything got very hot. Salt was added. After a while the

fat came to the top. When the cooked fat was taken out, it got hard. This was the first soap.

     The soap we use today is very different. Things were put in to make it smell good. Something is added

to give it a nice color. Some soaps are white. Others are yellow, green, or blue. Soap is also cut in different

ways. It can be round or square.

     What is soap used for? We all know that it is needed to wash things. But did you know that a kind of

soap is used to oil machines? This makes them work well. Another kind of soap is put in oil to make your

car run better.

1. What's the passage mainly about? ( answer the question briefly)

__________________________________________________________________________________

2. What's the meaning of the word" but then" in the first paragraph?

     ( answer the question briefly)

__________________________________________________________________________________

3. Which sentence in the passage can be replaced by the following one?

     People used the ashes to take over soap.

__________________________________________________________________________________

4. Fill in the blank with proper words or phrases to complete the sentence.

     People put pot on fire in order to ____________________________________________________.

5. Translate the underlined sentence into Chinese.

___________________________________________________________________________________