单选题

Light Night, Dark Stars

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, Colo. But when people are surrounded by city lights, he says, they're lucky to see 150 stars.
If you've ever driven toward a big city at night and seen its glow from a great distance, you've 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 stargazing 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 can't locate these objects, they can't learn more about them.
Light pollution doesn't only affect star visibility. It can harm wildlife too. It's clear that artificial light can attract animals, making them go off course. There's 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.

单选题 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

【答案解析】[解析] 第一段的第二句提供了答案。在没有云、没有月光、没有人造光源的情况下，可以看见14000颗星星，故本题选C。

单选题 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

【答案解析】[解析] A，B，C三项所述内容均可在第二段中找到。D项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”，故本题选D。

单选题 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

【答案解析】[解析] 答案在第五段中可以找到。随着城市规模的扩大，曾经昏暗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，故本题选A。

单选题 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

【答案解析】[解析] 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，故本题选B。

单选题 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

【答案解析】[解析] 题目的意思是：“城市灯火通明的夜晚使星星失去光泽。”C项内容符合题意，故本题选C。