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
A warm blanket is the ideal sleep aid for a freezing winter night. The right blanket can warm your bones but the wrong one can affect your sleep. I asked experts for advice on picking the perfect blanket for a good night’s sleep. Here’s what they told me.
When it comes to sleep temperature, experts recommend following the principle: not too cold, not too hot, but just right. “People seem to sleep best at temperature between 62 and 70 degrees F,” says Dr. Alice Hoagland. When the surrounding temperature falls too low, it can rouse you from sleep. A good blanket helps drive the coldness away.
At the other extreme, overheating yourself can affect your sleep as well. “Core body temperature typically drops during the first four hour’s of sleep,” says Dr. Hoagland. This decline in body temperature helps you fall asleep and stay asleep.
“In medical care, weighted blankets are one of our most powerful tools for helping people who are anxious, upset, and possibly losing control,” says Dr. Karen Moore. These special blankets are filled with weighted pellets. Weighted blankets are also marketed for general use as an aid to sleep and relaxation. Like a firm hug, weighted blankets help us feel safe.” This is the reason why many people like to sleep under a blanket even in summer.
“If you want to try this type of blanket, the best weight depends on your body size and personal preference. However, 15 to 30 pounds is typical for adults,” Moor says. She adds that weighted blankets are not recommended for those recovering from surgery.
“People can also have serious preferences for a particular blanket,” says Dr. Hoagland. “Regularly using a favorite blanket for sleep can help to develop a conditioned response so that sleep is quicker.” In fact, many sleep centers ask patients to bring their own blanket and pillow from home, which helps them fall asleep more easily.The author wrote the passage mainly to tell us _____.
| A．the importance of blankets |
| B．how to choose the perfect blanket |
| C．different materials used to make blankets |
| D．the history and usage of blankets |
The underlined word “rouse” in Paragraph 2 is the closest in meaning to “______”.
| A．wake up | B．take up | C．make up | D．pick up |
What do we know from the passage?
| A．Body temperature rises when we fall asleep |
| B．The perfect sleep temperature should be above 70 degrees F. |
| C．Weighted blankets should be at least 30 pounds. |
| D．People are advised to use their own blankets. |
The booking notes of the play “The Age of Innocence”.
Price: $10
BOOKING
There are four easy ways to book seats for performance:
-----in person
The Box Office is open from Money to Saturday, 10 a.m.----8 p.m.
-----by telephone
Ring 01324976 to reserve your tickets or to pay by credit card (Visa, Master Card and Amex accepted)。
-----on-line/online
Simply complete the booking form and return it to Global Theatre Box Office.
-----online/on-line
Complete the on-line booking form at www. Satanfiedtheatre. com.
DISCOUNT
Saver: $2 off any seat booked any time in advance for performances from Monday to Thursday. Savers are available for children up to 16 years old, those over 60 and full-time students.
Supersavers: half-price seats are available for people with disabilities and one companion. It is advisable to book in advance. There is a maximum of eight wheelchair spaces available and one wheelchair space will be held until an hour before the show.
Standby: best available seats are on sale for $6 from one hour before the performance for people eligible for Saver and Supersaver discounts and thirty minutes before for all other customers.
Group booking: there is a ten percent discount for parties of twelve or more.
School: school parties of ten or more can book $6 standby tickets in advance and will get every tenth ticket free.
PLEASE NOTE: we are unable to exchange tickets for refund money unless a performance is cancelled due to unpredicted circumstances.If you want to book a ticket, you CANNOT______.
| A．go to the Box Office on Sundays |
| B．use the Internet |
| C．ring the booking number and pay the tickets by credit card |
| D．complete a booking form and post it to the Box Office |
If you make a group booking for a group of 14 adults, how much should you pay?
| A．$120 | B．$126 | C．$140 | D．$150 |
Which of the following is NOT true according to the passage?
| A．There are only 8 wheelchair spaces in the theatre. |
| B．A school party of 15 students should pay $90 for the standby tickets. |
| C．Full-time students can get best seats for $6 from one hour before the performance. |
| D．The audience can’t refund money if the performance is on show. |
What kind of tickets are the cheapest?
| A．The standby tickets for school parties of ten or more. |
| B．The standby tickets. |
| C．The ticket for saver discount. |
| D．The tickets for group booking. |
An African-American man named John Henry was the hero of former slaves and the people who built the railroads in the US in the 19th century.
John Henry was born a slave. He was known for his strength. Many people say he represents the spirit of growth in America during that period.
John Henry grew up in a world that did not let children stay children for long. Before he was six years old, he was carrying stones for workers building a nearby railroad. By the time John Henry was a young man, he was one of the best railroad workers in the country.
John Henry was asked to lead workers on a hard project, creating a tunnel through a mountain. The project required about 1,000 laborers and lasted three years. Hundreds of men became sick as a result of the hot weather and tiredness. John Henry was the strongest and fastest man. Concerned his friends might lose their jobs, he picked up their hammers and began doing their work. He worked day and night, rarely stopping to have a rest.
One day, a salesman came to the work area with a new drilling machine powered by steam. He said it could drill holes faster than twelve men working together.
John Henry looked at the machine and saw images of the future. He saw machines taking the place of America’s best laborers. He saw himself and his friends unemployed and sanding by a road, asking for food. He decided he would never let the machine take their jobs. Therefore, a competition between a man and a machine began .At first, the steam-powered drill worked twice faster. Then, John Henry started working with a hammer in each hand. He worked faster and faster. People cheered when the machine broke down and was pulled away. But they were sad to find John Henry fall to the ground, with blood spilling all around, and still holding a hammer in one of his hands.“I beat them,”he said. Then he took his last breath.What does the underlined part in Paragraph 3 most probably mean?
| A．Many children in those days starved to death. |
| B．Children at that time grew much faster. |
| C．Children in those days had to work like adults. |
| D．Children at that time couldn’t stay together. |
Why did hundreds of workers become sick?
| A．Because they had to work long hours. |
| B．Because the weather was hot and they were tired. |
| C．Because the project was too hard. |
| D．Because they didn’t have time to eat. |
John Henry helped do his friends’ work .
| A．because he was the strongest and fastest man |
| B．for fear that his friends would lose their jobs |
| C．so that they could regain their strength |
| D．in order be the hero of the railroad workers |
Which of the following best describes John Henry?
| A．Kind and determined. | B．Cautious and considerate. |
| C．Brave and strict. | D．Hardworking and stubborn. |
Think about the different ways that people use the wind. You can use it to fly a kite or to sail a boat. Wind is one of our cleanest and richest power sources, as well as one of the oldest. Evidence shows that windmills(风车) began to be used in ancient Iran back in the seventh century BC. They were first introduced to Europe during the 1100s, when armies returned from the Middle East with knowledge of using wind power.
For many centuries, people used windmills to grind(碾碎) wheat into flour or pump water from deep underground. When electricity was discovered in the late 1800s, people living in remote areas began to use them to produce electricity. This allowed them to have electric lights and radios. However, by the 1940s when electricity was available to people in almost all areas of the United States, windmills were rarely used.
During the 1970s, people started becoming concerned about the pollution that is created when coal and gas are burned to produce electricity. People also realized that the supply of coal and gas would not last forever. Then, wind was rediscovered, though it means higher cost. Today, there is a global movement to supply more and more of our electricity through the use of wind.From the text we know that windmills________.
| A．were invented by European armies |
| B．have a history of more than 2,800 years |
| C．used to supply power to radio in remote areas |
| D．have rarely been used since electricity was discovered |
What was a new use for wind power in the late 19th century?
| A．Sailing a boat. |
| B．Producing electricity. |
| C．Grinding wheat into flour. |
| D．Pumping water from underground. |
One of the reasons wind was rediscovered in the 1970s is that_______.
| A．wind power is cleaner |
| B．it is one of the oldest power sources. |
| C．it was cheaper to create energy from wind |
| D．the supply of coal and gas failed to meet needs |
What would the author probably discuss in the paragraph that follows?
| A．The advantages of wind power. |
| B．The design of wind power plants. |
| C．The worldwide movement to save energy. |
| D．The global trend towards producing power from wind. |
When an ant dies, other ants take it out of the nest, often within an hour after its death. This behavior interests scientists and they wonder how ants know for sure—and so soon—that another ant is dead.
One scientist recently came up with a way to explain this ant behavior. Dong-Hwan Choe is a biologist, a scientist who studies animals and plants. He found that ants have a chemical on the outside of their bodies that signals to other ants, “I'm dead—take me away” when it is dead.
But there's a question to answer: As we know, if an ant is dead, it stops moving. But when an ant is sleeping or knocked unconscious, it is also not moving. However, other ants don't move the living ant out of the nest. How do they know this ant is not dead? Choe found that ants have another chemical on their bodies, which tells nearby ants something like, “Wait—I'm not dead yet” when it is not dead. Choe suspects that when an ant dies, the chemical that says, “Wait— I'm not dead yet” quickly goes away. When other ants detect the “dead” chemical without the “not dead yet” chemical, they move away the body.
To test his theory, Choe and his team put different chemicals on ants. When the scientists used the “I'm dead” chemical, other ants quickly moved the treated ant away. When the scientists used the “Wait—I'm not dead yet” chemical, other ants left the treated ant alone. Choe believes this behavior shows that the “not dead yet” chemical is stronger than the “dead” chemical when picked up by other ants. And that when an ant dies, the “not dead yet” chemical fades away. Other nearby ants then detect the remaining “dead” chemical and remove the body from the nest.
Understanding this behavior can help scientists figure out how to stop ants from invading new places and causing problems.What is the function of the first paragraph?
| A．Leading the following paragraphs. |
| B．Showing the main idea of the passage. |
| C．Introducing the background of the passage. |
| D．Giving a summary of the passage. |
What can we learn from the passage?
| A．Living ants can also be taken away when they are not moving. |
| B．When an ant dies, it can tell others using a certain chemical. |
| C．A living ant can pretend to be dead using a special chemical. |
| D．Ants often use chemicals to communicate with each other. |
Which of the following descriptions about Dong-Hwan Choe is right?
| A．Choe did this study in order to stop ants from invading new places. |
| B．Choe is a biologist who is only interested in animals, especially in ants. |
| C．Choe first came up with an idea to explain this ant behavior, and then did some tests to prove his theory. |
| D．Choe did the research on this ant behavior on his own. |
What is mainly discussed in the passage?
| A．experiments about how ants manage to keep their nests clean. |
| B．experiments about why ants have special chemicals on their bodies. |
| C．experiments about why ants can have this removal behavior |
| D．experiments about how to decide whether an ant is dead or not. |
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