问题补充：
When you look up into the sky at night, have you ever felt that your eyes are playing tricks on (捉弄) you? It seems that the stars are moving all the time.
Actually, there is nothing wrong with your eyes. This twinkling effect is called scintillation (交光). Scintillation happens because of air movements in the earth’s atmosphere (大气). Light is “bent (弯曲的)” when it travels through different parts of the earth’s atmosphere. As the air in the earth’s atmosphere is moving all the time, the light from the stars looks as if it is moving too.
The same thing also happens to things on the ground. On a very hot and shiny day, if you look at the road, the image in the distance is not clear and things move slightly. You can also see the same effect if you drop a rock into water. The rock appears a little unclear under the moving water.
This twinkling effect causes a lot of problems for astronomers (天文学家) since they cannot observe the stars clearly. A telescope (望远镜) was sent into space so that the air movements in the atmosphere could be avoided (避免). It took a long time to build the space telescope but finally in 1990, a huge space telescope called the Hubble Space Telescope was successfully sent into space. Since then, astronomers have many important observations that have helped people understand space better.
根据短文内容，选择最佳选项。 （10分）
【小题1】What happens to the light from the stars we see when the air in the earth’s atmosphere is moving? A．It looks even brighter.B．It looks as if it is bent.C．It looks as if it is moving.D．It looks like drops of rain.【小题2】Scintillation also happens on according to the passage. A．rainy daysB．shiny daysC．cloudy daysD．windy days【小题3】What can you see when you drop a rock into the water? A．The rock gets broken.B．The rock becomes unclear.C．The water becomes much polluted.D．The water does not move anymore.【小题4】The underlined word “observe” means “”.A．watchB．listenC．drawD．explain【小题5】Why is scintillation a problem for astronomers? A．The stars never stay still.B．It makes the stars too dark to see.C．It makes astronomers feel too hot to work.D．Astronomers cannot observe the stars clearly.C
答案：
(答案→)C
解析：这篇短文主要介绍了发生在大气中的一种重要的自然现象——交光现象，短文详细的介绍了这种现象的科学原理及其对宇航员工作的影响。
【小题1】根据第二段As the air in the earth’s atmosphere is moving all the time, the light from the stars looks as if it is moving too.描述，可知它看起来好像在移动，故选C。
【小题2】根据第三段The same thing also happens to things on the ground. On a very hot and shiny day, 描述，可知交光现象也可能发生在白天，故选B。
【小题3】根据第三段You can also see the same effect if you drop a rock into water. The rock appears a little unclear under the moving water.描述，可知石头变得看不清楚了。故选B。
【小题4】联系上下文，可知此处指的是，由于他们不能清楚地观察到星星。故选A，观察。
【小题5】根据最后一段This twinkling effect causes a lot of problems for astronomers (天文学家) since they cannot observe the stars clearly. 描述，可知因此宇航员就不能清晰地观察星星了。故选D。
