Can people change their skin color without suffering like pop king Michael Jackson? Perhaps yes. Scientists have found the gene that determines skin color.
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 color of a dark-striped zebrafish（斑马鱼） to uniform gold by inserting a version of the pigment (色素) gene into a young fish. As with humans, zebrafish skin color is determined by pigment cells, which contain melanin (黑色素). The number, size and darkness of melanin per pigment cell determine skin color.
It appears that, like the golden zebrafish, light-skinned Europeans also have a mutation (变异) in the gene for melanin 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 color, said Cheng.
The new discovery could lead to medical treatments for skin cancer. It also could lead to research into ways to change skin color without damaging it like chemical treatment did on Michael Jackson.
1.The passage mainly tells us that ________.
A. people can not change their skin color without any pain
B. the new discovery could lead to research into ways to change skin color safely
C. pop king Michael Jackson often changed his skin color as he liked
D. scientists have found out that people’s skin color is determined by the gene
2.It can be inferred from the passage that ________.
A. nowadays people who want to change their skin color 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
3.Scientists have done an experiment on a dark-striped zebrafish in order to ________.
A. find the different genes of humans’
B. prove the humans’ skin color is determined by the pigment gene
C. find out the reason why the Africans’ skin color is dark
D. find out the ways of changing people’s skin color
4.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 gene for melanin production
C. they have fewer activities outside
D. they pay much attention to protecting their skin
5.The writer’s attitude towards the discovery is ________.
A. neutral B. negative C. positive D. unconcerned
There has been a dramatic increase in the number of natural disasters over the past few years, and it is assumed that global warming and climate change could cause even more disasters in the future. Some of the world’s leading cities are facing disasters like floods and heat waves.
London
London’s flood defences are getting older. Since 1982, the Thames Barrier(水闸)has protected the city from the threat of flooding, but it was only designed to last until 2030 and close once every two or three years. About 26 years later the barrier now closes five or six times a year and according to Environment Agency predictions, by 2050 the barrier will be closed on almost every tide if the problem is not addressed.
There are 26 underground stations, 400 schools, 16 hospitals, an airport and 80 billion worth of property in London’s flood risk area, so large scale flooding would be disastrous.
Paris
Over a six week period in July and August 2003, more than 1 1,400—mainly elderly people—died in France from dehydration(脱水)and extremely high body temperature in a deadly heat wave. Heat waves of similar intensity(强度)are expected every seven years by 2050, so what can be done to make sure such a disaster does not happen again?
One solution is to have air-conditioners installed in elderly care homes. But this is considered a short-term solution, as the increase in demand for electricity also increases carbon emissions(排放).
In Paris the local authorities are encouraging architects to design new types of buildings such as the building “Flower Tower,” which uses a covering of bamboo to act as a natural air-conditioner.
Shanghai
Shanghai is the fastest growing city on Earth. It has a population of 18 million and is only 4 meters above sea level. Sea levels are predicted to rise by 20 cm within the next century.
An estimated 250，000 people move to Shanghai every year in search of work, placing extra demands on energy consumption. China relies heavily on coal—fired power stations, but these emissions increase temperatures and, in turn, warmer seas increase the risk of typhoons.
1.What problem should be settled now in London?
A．How to protect the city’s property
B．Where to build its flood defences
C．How to use the Thames Barrier to protect the city
D．How to improve the function of the old flood defences
2.Which of the following measures can’t solve the heat wave disaster in Paris?
A．Putting up new types of buildings with a covering of bamboo
B．Having air-conditioners installed in elderly care homes
C．Forbidding the city to build“Flower Tower”
D．Encouraging architects to design new types of buildings
3.The major threats to Shanghai are ．
A．increasing population and coal-fired power stations
B．rising sea levels and typhoons
C．extremely high temperature and rising sea levels
D．extra demands on energy consumption and typhoons
4.The purpose of the passage is ．
A．to tell us how to protect the big cities
B．to give advice on how to defend natural disasters
C．to explain what causes flood and heat waves
D．to warn us of the increasing natural disasters in big cities
5.Which of the following would be the best title for the passage?
A．Big Cities Facing Big Disasters
B．Big Disasters in the Future
C．The Increase of Natural Disasters
D．Solutions to Natural Disasters
Mark and his brother Jason both were looking at the shining new computer enviously. Jason was determined not to go against their father’s wishes but Mark was more adventurous than his brother. He loves experimenting and his aim was to become a scientist like his father.
“Dad will be really mad if he finds out you’ve been playing with his new computer” Jason said, “He told us not to touch it.”
“He won’t find out,” Mark said, “I’ll just have a quick look and shut it down.”
Mark had been scolded before for touching his father’s equipment. But his curiosity was difficult to control and this new computer really puzzled him.
It was a strange-looking machine — one his dad had brought home from the laboratory where he worked. “It’s an experimental model,” his father had explained, so don’t touch it under any circumstances.” But his father’s warning only served to make Mark more curious. Without any further thought, Mark turned on the power switch. The computer burst into life and seconds later, the screen turned into colours, shifting and changing, and then two big white words appeared in the centre of the screen: “SPACE TRANSPORTER.”
“Yes!” Mark cried excitedly, “It’s a computer game. I knew it! Dad’s only been pretending to work. He’s really been playing games instead!” A new message appeared on the screen:
“ENTER NAMES
VOYAGE １
VOYAGE ２
Mark’s finger flew across the keyboard as he typed in both of their names.
“INPUT ACCEPTED.
START TRANSPORT PROGRAM.
AUTO-RETRIEVE INITIATED(自动回收程序已启动).”
The screen turn even brighter and a noise suddenly rose in volume.
“I think we’d better shut it off, Mark,” Jason yelled out in terror, reaching for the power switch. A beam(光束) of dazzling white light burst out of the computer screen, wrapping the boys in its glow(光芒)，until they themselves seemed to be glowing. Then it died down just as suddenly as it had burst into life. And the boys were no longer there. On the screen, the letters changed：
“TRANSPORT SUCCESSFUL．
DESTINATION: MARS.
RETRIEVE DATE: 2025
1.Why did Mark touch the computer against his father’s warning?
A. He wanted to take a voyage.
B. He wanted to practice his skills.
C. He was so much attracted by it.
D. He was eager to do an experiment.
2.Where did the boy’s father most likely work?
A. In an electronic factory
B. In a computer company
C. In a scientific research center.
D. In an information processing center.
3.Mark thought “SPACE TRANSPORTER” on the screen was the name of ________.
A. a computer game B. a company website
C. a software producer D. an astronomy program
4.Why did Jason want to shut off the computer?
A. He was afraid of being scolded.
B. He didn’t like the loud noise and light.
C. He didn’t want to play games.
D. He was afraid something dangerous might happen.
5.What happened to the boys at the end of the story?
A. They were blown into the air.
B. They were sent to another planet.
C. They were hidden in the strong light.
D. They were carried away to another country.
阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填人一个适适的词或使用括号中词语的正确形式填空，并将答案填写在答卷标号的相应位置上。
There are times when people are so tired that they fall asleep almost anywhere. We can see a lot of people sleeping on the bus or train on their way home 1. work in the evening. A man will be reading the newspaper, and seconds later it appears as if he is trying to eat it. Or he will fall asleep on the shoulder of the stranger sitting next to him. Another place where 2. (plan) short sleep goes on is in the lecture hall 3. a student will start snoring so loudly that the professor has to ask 4. student to shake the sleeper awake. A more 5. (embarrass) situation occurs when a student starts falling into sleep and 6. weight of the head pushes the arm off the desk, and the movement carries the rest of the body along. The student wakes up on the floor with no memory of getting there. The 7. (bad) time to fall asleep is when driving. Police reports are full of accidents that occur when people fall into sleep and go off the road. 8. the drivers are lucky, they are not seriously hurt. One woman’s car, for example, went into the river. She woke up in four feet of water and thought that it 9. (rain). When people are really tired, 10. will stop them from falling asleep — no matter where they are.
Another secret of animals’ survival is telepathy（心灵感应）. This sense becomes atrophied（衰退） in man, but a(n) 1 thought-communication functions in animals. Elsa, the lioness, frequently 2 when George and I intended to visit her camp, even though it 3 180 miles from our home in Isiolo. On most 4 when we made our irregular visit she was waiting for us. By following the spoor（野兽的足迹），we 5 that she had sometimes walked 50 or 60 miles to meet us.
The same thing 6 when I took Elsa’s sisters to Nairobi to be flown to the Rotterdam zoo, Elsa’s zoo. Elsa stayed behind with George in Isiolo 180 miles 7 . He did not know when I was coming back, no person knew. But Elsa knew. On the morning of my 8 she sat down at the entrance and wouldn’t make any 9 until I arrived in the evening.
I have known this kind of thought-communication with the animal with whom I’ve lived. When Elsa died, I woke in the night, knowing what had happened, even though I was several miles away. The same thing 10 later with one of Pippa’s cubs.
I don’t 11 this sensitivity with my own kind. Feel far more in tune with what is going on when I am in the bush than when I am in London on Nairobi. We don’t know much yet about this telepathy from which gland（腺体） it comes, or how it 12 . But if men could awaken or 13 it in themselves, and then cooperate by trusting each other, 14 fearing and treating one another 15 , the world would be a far better place.
1.A. extremely B. completely C. thoroughly D. definitely
2.A. sensed B. aware C. feels D. concerns
3.A. lay B. lies C. located D. stood
4.A. case B. conditions C. occasions D. situations
5.A. discussed B. dismissed C. discovered D. distrusted
6.A. happened B. broken out C. replaced D. took over
7.A. far B. farther C. away D. far from
8.A. turn B. return C. reality D. reappear
9.A. emotions B. feelings C. exchanges D. movement
10.A.burst forth B. burst C. appeared D. occurred
11.A. command B. confirm C. possess D. prohibit
12.A. starts B. comprehends C. manufactures D. works
13.A. create B. plant C. cultivate D. produce
14.A. rather than B. other than C. would rather D. or rather
15.A.suspiciously B. suspecting C. prosperously D. doubtfully
The weather turned out to be fine. I the trouble to carry the umbrella with me.
A. should have taken B. needn’t have taken
C. mustn’t have taken D. could have taken
