卫生类：阅读理解Light Night
Thousands of people around the globe step outside to gaze at their night sky. On a clear night， with no clouds， moonlight， or artificial lights to block the view， people can see more than 14，000 stars in the sky， says Dennis Ward， an astronomer with the University Corporation for Atmospheric Research (UCAR) in Boulder， Colo1. But when people are surrounded by city lights， he says， theyre lucky to see 150 stars.
If youve ever driven toward a big city at night and seen its glow from a great distance， youve witnessed light pollution. It occurs when light from streetlights， office buildings， signs， and other sources streams into space and illuminates the night sky. This haze of light makes many stars invisible to people on Earth. Even at night， big cities like New York glow from light pollution， making stargazing2 difficult.
Dust and particles of pollution from factories and industries worsen the effects of light pollution. "If one city has a lot more light pollution than another，" Ward says， "that city will suffer the effects of light pollution on a much greater scale. "
Hazy skies also make it far more difficult for astronomers to do their jobs.
Cities are getting larger. Suburbs are growing in once dark， rural areas. Light from all this new development is increasingly obscuring the faint light given off by distant stars. And if scientists cant locate these objects， they cant learn more about them.
Light pollution doesnt only affect star visibility. It can harm wildlife too. Its clear that artificial light can attract animals， making them go off course3. Theres increasing evidence， for example， that migrating birds use sunsets and sunrises to help find their way， says Sydney Gauthreaux Jr.， a scientist at Clemson University in South Carolina. "When light occurs at night，" he says， "it has a very disruptive influence. " Sometimes birds fly into lighted towers， high-rises， and cables from radio and television towers. Experts estimate that millions of birds die this way every year.
41.When can people see 14，000 stars
A.When they have a fairly good telescope.
B.When they are in a large city.
C.When the night sky is clear of clouds， moonlight and artificial lights.
D.When the night sky is without haze and fog.
正确答案：C
解析：问题问的是：什么时候人们能看到14000颗星星？第一段的第一句提供了答案。在没有云，没有月光，没有人造光源的情况下，可以看见14，000颗星星。
42.Which of the following statements is NOT related to light pollution
A.A haze of light is formed from artificial lights such as streetlights and building lights.
B.Lights from different sources stream into space and illuminate the night sky.
C.The night sky is illuminated by the lights from big glowing cities in the night.
D.Stargazing becomes difficult because there is a layer of haze in the air
正确答案：D
解析：问题问的是：以下说法哪个与光污染无关？A.B.C所述内容均可在第二段中找到。D所表达的意思不符合原文，因为a layer of haze in the air的意思是“空气中有一层薄雾”。
43.Why does the writer think growing cities affect astronomers work
A.Because the once dark rural areas are polluted by lights.
B.Because they can still see stars in rural areas.
C.Because rural areas are not a good place for astronomers to study stars.
D.Because faint light given off by stars can still be seen on a clear night
正确答案：A
解析：问题问的是：为什么作者认为城市规模的扩大会影响宇航员的工作？答案在第五段中可以找到。随着城市规模的扩大，曾经黑灯瞎火的乡村逐渐变成了市郊，那里的灯火使科学家无法观测到星体发出的微弱光芒。
44.Which of the following is NOT correct
A.Animals may go off course due to the attraction of artificial lights.
B.Animals might be attracted by artificial lights to go into cities.
C.Artificial lights at night may make migrating birds lose their way.
D.Attracted by artificial lights， birds fly into lighted buildings.
正确答案：B
解析：问题问的是：以下说法哪个是错误的？第六段最后三句告诉我们人造光源会误导动物而致使它们迷路，但却没有说会将它们引进城市。
45.Which of the following is closest in meaning to the title "Light Night， Dark Stars"
A.The night sky is light colored and stars are black.
B.Lights appear at night and stars are seen in the dark.
C.City lights illuminate the night sky and make stars invisible.
D.City lights at night illuminate stars in the sky.
正确答案：C
解析：问题问的是：以下说法哪一个与题目最为相似？题目的意思是：城市灯火通明的夜晚使星星失去光泽。