第三部分：阅读理解（共20小题，每题2分，满分40分）阅读下-优题课

Against the supposition than forest fires in Alaska, Canada and Siberia warm the climate, scientists have discovered that cooling may occur in areas where burnt trees allow more snow to mirror more sunlight into space.
This finding suggests that taking steps to prevent northern forest to limit the release of greenhouse gases may warm the climate in northern regions. Usually large fires destroyed forests in these areas over the past decade. Scientists predict that with climate warming, fires may occur more frequently over next several centuries as result of a longer fire season. Sunlight taken in by the earth tends to cause warming, while heat mirrored back into space tends to cause cooling.
This is the first study to analyze all aspects of how northern fires influence climate. Earlier studies by other scientists have suggested that fire in northern regions speed up climate warming because greenhouse gases from burning trees and plants are released into the atmosphere and thus trap heat.
Scientists found that right after the fire, large amounts of greenhouse gases entered the atmosphere and caused warming. Ozone（臭氧）levels increased, and ash from the fire fell on far-off sea ice, darkening the surface and causing more radiation from the sun to be taken in. The following spring, however, the land within the area of the fire was brighter than before the fire, because fewer trees covered the ground. Snow on the ground mirrored more sunlight back into space, leading to cooling.
“We need to find out all possible ways to reduce the growth of greenhouse gases in the atmosphere.” Scientists tracked the change in amount of radiation entering and leaving the climate system as a result of the fire, and found a measurement closely related to the global air temperature. Typically, fire in northern regions occurs in the same area every 80 to 150 years. Scientists, however, found that when fire occurs more frequently, more radiation is lost from the earth and cooling results. Specifically, they determined when fire returns 20 years earlier than predicated, 0.5 watts per square meter of area burned are soaked up by the earth from greenhouse gases, but 0.9 watts per square meter will be sent back into space. The net effect is cooling. Watts are used to measure the rate at which energy is gained or lost from the earth.
46. According to the new findings, taking steps to prevent northern forest fires may _______.
A. result in a warming climate
B. cause the forest fires to occur more frequently
C. lead to a longer fire season
D. protect the forests and the environment there
47. The following are all the immediate effects after a forest fire EXCEPT _________.
A. large amounts of greenhouse gases enter the atmosphere
B. the levels of ozone which is a type of oxygen increase
C. snow on the ground mirrors more sunlight back into space
D. ashes from the fire fall on the ice surface and take in more radiation from the sun
48. Earlier studies about northern forest fires _________.
A. analyze all aspects of how northern fires influence climate
B. indicate that forest fires will pollute the atmosphere
C. suggest that people should take measures to protect environment
D. suggest that the fires will speed up climate warming
49. The underlined phrase “soak up” in the last paragraph most probably means ________.
A. released B. absorbed C. created D. distributed
50. From the passage we can draw a conclusion that forest fires in Alaska, Canada and Siberia may __________.
A. warm the climate as the supposition goes
B. allow more snow to reflect more sunlight into space and thus cool the climate
C. destroy large areas of forests and pollute the far-off sea ice
D. help to gain more energy rather than release more energy

A little under one-third of U.S. families have no Internet access and do not plan to get it, with most of the holdouts seeing little use for it in their lives, according to a survey released on Friday.
Park Associates, a Dallas-based technology market research firm, said 29 percent of U.S. families, or 31 million homes, do not have Internet access and do not intend to subscribe（预订）to an Internet service over the next 12 months. The second annual National Technology Scan conducted by Park found that the main reason why potential customers say they do not subscribe to the Internet is because of the low value to their daily lives rather than concerns over cost.
Forty-four percent of these families say they are not interested in anything on the Internet, versus just 22 percent who say they cannot afford a computer or the cost of Internet service, the survey showed. The answer “I’m not sure how to use the Internet” came from 17 percent of participants who do not subscribe. The response “I do all my e-commerce shopping and YouTube-watching at work” was cited by 14 percent of Internet-access users. Three percent said the Internet doesn’t reach their homes.
The study found U.S. broadband adoption grew to 52 percent over 2006, up from 42 percent in 2005. Roughly half of new subscribers converted（转变）from slower-speed, dial-up Internet access while the other half of families had no prior access.
“The industry continues to chip（击破）away at the core of non-subscribers, but has a long way to go,” said John Barrett, director of research at Parks Associates. “Entertainment applications will be the key. If anything will pull in the holdouts, it’s going to be applications that make the Internet more similar to pay-TV,” he predicted.
41. What does the underlined word “holdouts” in the first paragraph most probably mean?
A. some American families
B. those who hold out one’s opinions
C. those who have been surveyed
D. those who still haven’t access to the Internet currently
42. Many potential customers refuse to subscribe to the Internet mainly because _________.
A. they show too much concern about the cost B. they can find little value of it
C. they do most YouTube-watching at work D. the Internet doesn’t reach their homes
43. From the passage we can infer that ________.
A. It is not an easy job to transform those holdouts into the Internet users
B. people will adopt dial-up Internet access no more
C. many Americans enjoy doing e-commerce shopping at home
D. more than half of the population are using the Internet in 2005
44. According to John Barrett, what is the key to attracting more U.S. families to broadband service?
A. making the Internet look more similar to TV set
B. applying the Internet more to entertainment
C. providing more pay-TV programs
D. chipping away at the core of non-subscribers
45. Which is the best title for the passage?
A. Web develops with technology B. The present situation of web
C. Many Americans see little point to web D. It is urgent to promote web service

There are many thoughts on the origins of civilization. One of the major factors involved was the increase in population. The development of techniques, primarily irrigation and flood control, which permitted agriculture in special areas such as the flood plain of the Tigris and Euphrates rivers, made possible the support of large population. Once populations reach a certain number, the older pattern of social organization breaks down and new ones develop. Specifically the older system, whereby each individual participated in food production and maintained a similar standard of living and whereby kinship(家属关系) served as the basic method of social organization, was replaced by the occupational division of labor, political and religious hierarchies(等级制度), public works such as road and public building construction, class systems, codes of law, markets, new forms of warfare, and urban centres. Allied with these important sociological traits are material traits, such as monumental architecture and the development of science and, in many cases, metallurgy(冶金学) and writing sustems.
The earliest civilization, Sumer, developed in the Middle East. This was the Bronze Age of the Old World, during which people first developed the art of metallurgy, civilization also arose in other parts of the Old World, first in Eygpt, China, and India, and later in Europe and Africa. At this time, civilization also developed independently in the New World, in the Mexican area and in Peru and its adjacent(邻近的) areas.
In the Old World the Bronze Age was followed by the Iron Age, which saw the rise and fall of great empires and the shift of power from the Middle East to Greece and Rome and then to Western Europe. In the 1700s the Industrial Age began, leading directly to the modern civilization of today.
46. The author of this passage __________________________________.
A. gives a comparison between ancient civilization and modern civilization
B. suggests that population increase is most important in the development of civilization
C. tries to explain how civilization developed in human history
D. explore the relation between agriculture and industry
47. According to the first paragraph, the increase in population _____________________.
A. resulted in the development of agricultural technology
B. resulted from the breakdown of old social organization
C. caused the occupational division of labor
D. was impossible without the development of agriculture
48. The word “traits” in Paragraph One most likely means ___________________________.
A. main appearances B. great achievements
C. distinguishing features D. outstanding successes
49. Which of the following is NOT true according to the passage?
A. The Bronze Age is one of the earliest civilizations.
B. The Industrial Age started in the Middle East.
C. The Bronze Age developed into the Iron Age.
D. The use of metal instruments started from the Bronze Age.
50. Which of the following is NOT included in the expression “the Old World” used in the passage?
A. American continent. B. Both Western and Eastern Europe.
C. African continent. D. Asian countries.

Moving in with a boyfriend causes women to eat more unhealthily and put on weight. But the opposite is true for men, whose long-term health benefits when they move in with a female partner.
Dieticians at Newcastle University said both partners try to please one another, and so change their dietary habits to suit their other half.
It leads men to eat more light meals, such as salads, fruit and vegetables, while women choose to make creamier, heavier dishes curry or rich pasta sauces, which may please their partner.
Women still have the strongest long-term influence over the couple’s diet and lifestyle, as they still have the traditional role of shopper and cook in most households.
The report, by Newcastle University’s Human Nutrition Research Centre, reviewed the finding of a variety of research projects from the UK, North America and Australia, which looked at the eating and lifestyle habits of couples.
The research shows that women are more likely to put on weight and increase their consumption of foods high in fat and sugar when they move in with their partner.
Women also use food as a comfort when dealing with emotional stress and have been found to gain weight when a relationship ends, while the same finding has not been observed in men.
Many couples reported food as being central to their partnership, and eating together in the evening was particularly important to many.
Report author and registered dietician Dr. Amelia Lake said, “The research has shown that your partner is a strong influence on lifestyle and people who are trying to live healthier lives should take this factor into consideration.”
41. According to the passage, moving in with a girlfriend, men _______.
A. have few changes of their dietary habits
B. have to eat more unhealthy foods
C. don’t like foods high in fat and sugar at all
D. try to eat foods that their girlfriends like
42. The underlined word “light”(in Paragraph 4 ) probably means ________.
A. not very heavy
B. less in fat and sugar
C. gentle
D. not serious or important
43. According to the report by Newcastle University’s Human Nutrition Research Centre, ________.
A. women put on weight only because they want to suit their other half
B. when men are faced with emotional stress, they will change their dietary habits
C. eating together in the evening is a good way to communicate for couples
D. it is wrong to change your dietary habits to suit your partner
44. From the passage, we can infer that _________.
A. women should pay more attention to their partner’s influence on them
B. more men will play roles of shopper and cook in most households
C. couples will not change their dietary habits and lifestyle to please their partner
D. long-term health of men benefits when they move in with a female partner
45. What would be the best title for the passage?
A. Don’t be silly any more, women!
B. Which are better dietary habits?
C. Boyfriends make you fat
D. Dr. Amelia Lake and his study

Can people change their skin colour without suffering like pop king Michael Jackson? Perhaps yes. Scientists have found the gene that determines skin colour.
The gene comes in two versions, one of which is found in 99 per cent of Europeans. The other is found in 93 to 100 per cent of Africans, researchers at Pennsylvania State University report in the latest issue of Science.
Scientists have changed the colour of a dark-striped zebrafish to uniform gold by inserting a version of the pigment(色素) gene into a young fish. As with humans, zebrafish skin colour is determined by pigment cells, which contain melanosomes(黑色素). The number, size and darkness of melanosomes per pigment cell determines skin colour.
It appears that, like the golden zebrafish, light-skinned Europeans also have a mutation(变异) in the gene for melanosome production. This results in less pigmented skin.
However, Keith Cheng, leader of the research team, points out that the mutation is different in human and zebrafish genes.
Humans acquired dark skin in Africa about 1.5 million years ago to protect bodies from ultra-violet rays of the sun(太阳光紫外线), which can cause skin cancer.
But when modern humans leave Africa to live in northern latitudes, they need more sunlight on their skin to produce vitamin D. So the related gene changes, according to Cheng.
Asians have the same version of the gene as Africans, so they probably acquired their light skin through the action of some other gene that affects skin colour, said Cheng.
The new discovery could lead to medical treatments for skin cancer. It also could lead to research into ways to change skin colour without damaging it like chemical treatment did on Michael Jackson.
51. The passage mainly tells us that ________.
A. people can not change their skin colour without any pain
B. the new discovery could lead to search into ways to change skin colour safely
C. pop king Michael Jackson often changed his skin colour as he liked
D. scientists have found out that people’s skin colour is determined by the gene
52. It can be inferred from the passage that ________.
A. nowadays people who want to change their skin colour have to suffer a lot from the damage caused by the chemical treatment
B. Europeans and Africans have the same gene
C. the new discovery could help to find medical treatments for skin cancer
D. there are two kinds of genes
53. Scientists have done an experiment on a dark-striped zebra fish in order to ________.
A. find the different genes of humans’
B. prove the humans’ skin colour is determined by the pigment gene
C. find out the reason why the Africans’ skin colour is dark
D. find out the ways of changing peopl’s skin colour
54. The reason why Europeans are light-skinned is probably that ________.
A. they are born light-skinned people
B. light-skinned Europeans have mutation in the gen for melanosome production
C. they have fewer activities outside
D. they pay much attention to protecting their skin
55. The writer’s attitude towards the discovery is ________.
A. neutral B. negative C. positive D. indifferent