Their cheery song brightens many a winter's day.But robins are in danger of wearing themselves out by singing too much.Robins are singing all night-as well as during the day,British-based researchers say.

　　David Dominoni,of Glasgow University,said that light from street lamps,takeaway signs and homes is affecting the birds' biological clocks,leading to them being wide awake when they should be asleep.

　　Dr Dominoni,who is putting cameras inside nesting boxes to track sleeping patterns,said lack of sleep could put the birds' health at risk.His study shows that when robins are exposed to light at night in the lab,it leads to some genes being active at the wrong time of day.And the more birds are exposed to light,the more active they are at night.

　　He told people at a conference,"There have been a couple of studies suggesting they are increasing their song output at night and during the day they are still singing.Singing is a costly behaviour and it takes energy.So by increasing their song output,there might be some costs of energy."

　　And it is not just robins that are being kept awake by artificial light.Blackbirds and seagulls are also being more nocturnal.Dr Dominoni said,"In Glasgow where I live,gulls are a serious problem.I have people coming to me saying 'You are the bird expert.Can you help us kill these gulls?'.During the breeding(繁殖)season,between April and June,they are very active at night and very noisy and people can't sleep."

　　Although Dr Dominoni has only studied light pollution,other research concluded that robins living in noisy cities have started to sing at night to make themselves heard over loud noise.

　　However,some birds thrive(兴旺) in noisy environments.A study from California Polytechnic University found more hummingbirds in areas with heavy industrial machinery.It is thought that they are capitalising on their predators(天敌)fleeing to quieter areas.

5.According to Dr Dominoni's study,what causes robins to sing so much?

A.The breeding season.

B.The light in modern life.

C.The dangerous environment.

D.The noise from heavy machinery.

提示:细节理解题。由第二段中的"...light from street lamps,takeaway signs and homes is affecting the birds' biological clocks,leading to them being wide awake when they should be asleep."可知,街灯、外卖店的招牌和住宅产生的人造灯光会影响鸟的生物钟,导致它们在本应睡眠的夜间十分清醒。故B项正确。

答案:B

6.What is the researchers' concern over the increase of birds' song output?

A.The environment might be polluted.

B.The birds' health might be damaged.

C.The industry cost might be increased.

D.The people's hearing might be affected.

提示:推理判断题。 根据第四段最后一句话"...by increasing their song output,there might be some costs of energy."可以推断,这些鸟的健康可能会受损害,所以B项正确。

答案:B

7.What does the underlined word "nocturnal" in Paragraph 5 mean?

A.Active at night.

B.Inactive at night.

C.Active during the day.

D.Inactive during the day.

提示:词义猜测题。分析"And it is not just robins that are being kept awake by artificial light. Blackbirds and seagulls are also being more nocturnal."可以判断,画线单词和awake属于含义相近的词,都表示光污染也会使它们清醒或者活跃。nocturnal意为"夜间活动的",故A项正确。

答案:A

8.Why do some birds thrive in noisy environments?

A.Because there are fewer dangers.

B.Because there is more food to eat.

C.Because there is less light pollution.

D.Because there are more places to take shelter.