问题 单项选择题

地球南北极上空,经常出现极光,下列关于极光成因的正确说法是( )。

A.在地球南北两极,磁场活动异常活跃,磁场与大气层中的气体发生作用,形成了色彩艳丽的极光
B.地球南北两极气流活动活跃,气流与太阳光交互作用,摩擦放电,形成了极光
C.来自太阳的高能粒子,在地磁作用下,聚集到南北两极,并且与大气层中的粒子冲撞产生了极光
D.南北两极大气层比其他地区厚,折射太阳光线的能力强,照射到南北地区的光线大部分被折射回去,形成了极光

答案

参考答案:C

解析: 极光是太阳风中的高能粒子与地磁发生作用后发出的光,而不是反射或折射太阳光,排除 D,而A、B选项有关磁场活动异常活跃,两极气流活动活跃的说法并不科学,且其所论述的极光产生的原理也不科学;故正确答案是C。

单项选择题
阅读理解

Most British telephone cards are just plain green, but card collecting is becoming a popular hobby in Britain and collectors even have their own magazine, International Telephone Cards. One reason for their interests is that cards from around the world come in a wide variety of different and often very attractive design. There are 100, 000 different cards in Japan alone, and there you can put your own design onto a bank card simply by using a photograph or a business card.

The first telephone cards, produced in 1976, were Italian. Five years later the first British telephone cards appeared, and now you can buy cards in more than a hundred countries. People usually start collecting cards because they are attractive, small and light, and they do not need much space. It is also a cheap hobby for beginners, although for some people it becomes a serious business. In Paris, for example, there is a market where you can buy only telephone cards, and some French cards cost up to 4,000 pounds. The first Japanese card has a value of about 28,000 pounds. Most people only see cards with prices like these in their collectors’ magazine.

1. The passage is mainly about ______.

A. the history of phone cards           B. phone cards collecting as a hobby

C. reasons for phone cards collecting     D. the great variety of phone cards

2. When did people in Britain begin to use phone cards?

A. In 1971.            B. In 1975.            C. In 1976.            D. In 1981.

3. The main reason for most people to collect phone cards is that ______.

A. they find the cards beautiful and easy to keep

B. they like to have something from different countries

C. they want to make money with cards

D. they think the cards are convenient to use

4. The writer mentions a market in Paris in order to show that

A. card collecting is popular among young people

B. French and Japanese cards are the most valuable

C. people can make money out of card collecting

D. card collectors’ magazines are very useful