问题 选择题

常德市随着航天技术的飞速发展,我国已成功实现三次载人航天飞行,当飞船的轨道舱和返回舱一起进入预定圆形轨道绕地球飞行的时,下列说法错误的是(  )

A.因为飞船离地面高度的始终相同,故飞船相对地面是静止的

B.以轨道舱为参照物,返回舱是静止的

C.在大气层外宇航员透过舷窗看星星没有闪烁的感觉

D.通过无线电波,地面技术人员可以对飞船进行控制及与宇航员通话

答案

A选项中尽管飞船地面高度的始终相同,但是二者速度不同,所以A错误;

B选项中被选择的参照物相对飞船没有发生位置改变,所以B正确;

C选项中在大气层外宇航员透过舷窗看星星没有闪烁的感觉是因为星光经大气折射进入人眼,且大气在运动导致折射光变化,在大气层外,无大气也就不闪烁了.所以C正确;

因为电磁波可以在真空中传播,所以D选项正确.

故选A.

阅读理解

阅读理解。

    Our factories and homes burn coal and oil. Every year we have forest fires somewhere. Many scientists

believe that the weather is changing.

    The earth will perhaps be warmed by about 7℃ at the South Pole (极) and the North Pole. The ice will

be melt (融化). The sea level (平面) will rise by about 7 meters. As a result, water will cover cities like

London, Tokyo and New York. Some ports (港口) and towns along the coasts will disappear under water.

    Some other scientists think that the dust, smoke and pollution from coal, wood and oil fires will block

out (封闭) the ultraviolet rays (紫外线). Then the earth will become colder and great sheets of ice will

cover Europe and North America. 

    When chemicals in the air mix with rain, we have acid (酸) rain. Acid rain can bring us great harm. It

destroys (破坏) forests and kills life in lakes and rivers.

    People are beginning to see how serious the problem is. They find it important to work with nature

instead of against it. They are trying to save the earth in many different ways. But one of the most important

things to do is to make people understand that saving the earth is saving ourselves.

1. Some scientists believe that            . [ ]

A. the earth is growing warmer

B. we need coal in our forests

C. we can find oil in our forests

D. we have to burn down the forests every year

2. Ice at the poles will             if the earth gets warmer. [ ]

A. become thicker by seven meters

B. cover cities like London and Tokyo

C. raise the sea level by 7 degrees

D. become water and make the sea rise

3. Acid rain can            . [ ]

A. bring great changes in our weather

B. kill pests (害虫) in lakes and forests

C. kill the fish in rivers and lakes

D. cover Europe and North America

4. What can we learn from the third paragraph? [ ]

A. The dust together with pollution from coal, wood and oil fires will bring us more heat from the sun.

B. The ultraviolet rays will come more because of the dust and pollution from fires.

C. According to the scientists, the change in weather hardly has anything to do with the pollution.

D. As a result of the dust and pollution from coal, wood and oil fires, the earth will become colder.

问答题