The boy lying in the bed _______ to his friend that a cock _______ an egg yesterday.
A. lay; lay B. lay; lain C. lied; laid D. lied; lay
She _______ the film. She knows nothing about it.
A. can’t see B. can’t have seen C. must see D. mustn’t have seen
— Could I use your dictionary?
— Sure you ______. _______.
A. can; Go ahead B. can; Use it C. could; Help yourself D. could; Take it
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 dif ferent 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 vit amin D. So the related gene changes, according to Cheng.
Asians have the same version of the gene as Africans, so they pr obably 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.
1.. 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
2.. 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
3.. 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 melanosome production
C. they have fewer activities outside
D. they pay much attention to protecting their skin
For many people in the US，sports are not just for fun. They’re almost a “religion”．Thousands of sports fans buy expensive tickets to watch their favorite teams and athletes play in person .Other fans watch the games at home，sticking to their TV sets，never missing a game. Many a wife becomes a “sports widow” during her husband’s favorite season. Americans’ devotion to sports has created a new class：professional athletes. Sports stars often receive milliondollar salaries. Some even make big money by appearing in advertisements for soft drinks，shoes and almost everything.
Sports are an important part of American culture. Throughout their school life，Americans learn to play many sports. Many students try out for the school teams. Athletic events at universities attract scores of fans and benefit the whole community. Many people also enjoy noncompetitive activities，like hiking，cycling，horseback riding，camping or hunting.
Many sports were imported from other countries. Europeans brought tennis，golf，bowling and boxing to America .Football and baseball came from other Old World games. Only basketball has a truly American origin. Americans export sports fever as well. Satellites broadcast games to sports fans around the globe. NBA is a good example. The names of American superstars like basketball great Michael Jordan have become household words all over the world.
1.．Many a wife becomes a “sports widow” in the US probably because________.
A．they are serious in religion
B．they are devoted to sports
C．their husbands stick to sports
D．their husbands are missing
2.．Which of the following is NOT true according to the passage?
A．The US sports stars can earn a large sum of money via the media.
B．American students go in for various sports and athletic events.
C．Lots of American people take part in noncompetitive activities.
D．American people like to exchange different sports from each other.
3.．The writer mainly intends to tell us________.
A．how important sports are in America
B．where sports can help to make money
C．why sports are so popular in America
D．what affect Americans’ everyday life
Far from the land of Antarctica, a huge shelf of ice meets the ocean. At the underside of the shelf there lives a small fish, the Antarctic cod.
For forty years scientists have been curious about that fish. How does it live where most fish would freeze to death? There must be some secrets. The Antarctic is not a comfortable place to work and research has been slow. Now it seems we have an answer.
Research was begun by cutting holes in the ice and catching the fish. Scientists studied the fish's blood and measured its freezing point.
The fish were taken from seawater that had a temperature of -1.88℃ and many tiny pieces of ice floating in it. The blood of the fish did not begin to freeze until its temperature was lowered to -2.05℃. That small difference is enough for the fish to live at the freezing temperature of the ice-salt mixture.
The scientists' next research job was clear: find out what in the fish's blood kept it from freezing. Their search led to some really strange things made up of a protein(蛋白质) never seen in the blood of a fish before. When it was removed, the blood froze at seawater temperature. When it was put back, the blood again had its antifreeze quality and a lowered freezing point.
Study showed that it is an unusual kind of protein. It has many small sugar molecules(分子) held in special positions within each big protein molecule. Because of its sugar content, it is called a glycoprotein. So it has come to be called the antifreeze fish glycoprotein, or AFGP.
1. What is the text mainly about?
A. The terrible conditions in the Antarctic. B. A special fish living in freezing waters.
C. The ice shelf around Antarctica. D. Protection of the Antarctic cod.
2. Why can the Antarctic cod live at the freezing temperature?
A. The seawater has a temperature of -1.88℃.
B. It loves to live in the ice-salt mixture.
C. A special protein keeps it from freezing.
D. Its blood has a temperature lower than -2.05℃.
3. What does "glycol-" in the underlined word "glycoprotein" in the last paragraph mean？
A. sugar B. ice C. blood D. molecule
