Have you ever heard a news reporter talk about DNA? Reporters talk about DNA found at the scene of a crime. They talk about police finding DNA “fingerprints.” Police sometimes use DNA as a clue to find out who committed the crime.
DNA is a substance（物质） that makes up genes. Everything alive has genes. Plans have genes. Animals have genes. Yo
u have genes.
Genes are the basic units of heredity（遗传）. Heredity means all the characteristics you inherit from your parents. You get your genes from your parents. You inherit half of your genes from your mother. You inherit half of your genes from your father.
Genes are a kind of code. A tree’s genes tell w
hat shape its leaves will be. A cat’s genes tell what color its fur will be. Your genes tell what color your eyes will be. Your genes tell what color your hair will be. Everything about you co
mes from the code in your genes.
Genes line up on strands（链） called chromosomes（染色体） in cells. Everything alive is made up of cells. Chromosomes are in the center, or nucleus, of cells.
Different parts of you are made of different kinds of cells. Your muscles are made of muscle celIs. Your skin is made of skin cells. The code in your genes tells your body to make different kinds of cells. The genes in each cell tell the cell how to work. They tell the cell when to make new copies of itself.
An Austrian monk named Gregor Mendel first saw inherited patterns in pea plants. He experimented with pea plants in the 1860s. One of the things, or traits（特质）， Mendel studied was what makes some pea plants tall and some short. He said that the traits must come from units of heredity passed from the parent plants. These units were later called genes.
In the mid-1900s, scientists discovered that genes are made of DNA. In the 1970s, scientists learned how to change DNA with genetic engineering. Scientists also learned that problems with certain genes cause diseases. Muscular dystrophy, cystic fibrosis, and hemophilia are some genetic diseases-diseases caused by problems in genes. Today, scientists are looking for ways to cure genetic diseases by changing genes through a process called gene therapy. What is DNA?
| A．DNA is a kind of gene. |
| B．DNA is a substance that makes up genes. |
| C．DNA is the basic unit of heredity. |
| D．DNA is a measure to protect crime. |
Which of the following about genes is correct according to the passage?
| A．Plants, animals and human beings have the same genes. |
| B．Half people inherit all genes from their mother, others from their father. |
| C．Genes decide the trees shapes, the cats’ fur color and our eyes’ color as well. |
| D．Genes will give you a code when you need them. |
Where are genes?
| A．Genes lining up on strands called chromosomes are in the center of cells. |
| B．Genes hide in everything alive in your body. |
| C．Genes can be nowhere but in your mind, controlling all your actions. |
| D．Genes travel in your body and help cope skin, muscle, and eyes. |
An Austrian monk named Gregor Mendel .
| A．first saw inherited patterns in people |
| B．was interested in why plants were different |
| C．first called the units of heredity from parents genes |
| D．was the first who discovered genes |
We can conclude that .
| A．scientists were less intelligent than monks in 1900s |
| B．some genes are bad and can cause diseases |
| C．we don’t need to worry about genetic diseases any longer |
| D．the discovery of genes may be of great help in our daily life |
The meaning of the word “volunteer” may be a little different in different countries, but it usually means “one who offers his or her services．” There are many different ways in which people can volunteer, such as taking care of sick people, working in homes for homeless children, and picking up garbage from beaches and parks．Volunteers may work within their own countries or in other countries．They are often people with a strong wish to help those who are less fortunate than themselves．Volunteers don’t expect any kind of pay．
At the root of volunteering is the idea that one person may have the ability to offer services that can help other people．Tracy, a good friend of mine, however, recently came back from India with a new idea of what being a volunteer means．She worked for two and a half weeks in one of Mother Teresa’s homes in Calcutta．The following is her story．
“I first heard about Mother Teresa in my high school．We watched a video about her work in India and all over the world．I was so moved by her spirit to help others and her endless love for every human being that after I graduated from high school, I too wanted to try her kind of work．So with two friends I flew to Calcutta for a few weeks．”
“I was asked to work in a home for sick people．I helped wash clothes and sheets, and pass out lunch．I also fed the people who were too weak to feed themselves and tried to cheer them up．I felt it was better to share with them than to think that I have helped them．To be honest, I don’t think I was helping very much．It was then that I realized that I had not really come to help, but to learn about and experience another culture that helped improve my own understanding of life and the world．”According to the text, a volunteer refers to a person who ______．
| A．is willing to help those in need without pay |
| B．can afford to travel to different places |
| C．has a strong wish to be successful |
| D．has made a big fortune in life |
Tracy started her work as a volunteer _______．
| A．after she met Mother Teresa |
| B．after she finished high school |
| C．when she was touring Calcutta |
| D．when she was working in a hospital |
Why did Tracy choose to be a volunteer?
| A．She liked to work with Mother Teresa． |
| B．She had already had some experience． |
| C．She was asked by Mother Teresa’s example．k.s.5.u |
| D．She wanted to follow Mother Teresa’s example． |
Runners in a relay（接力） race pass a stick in one direction．However, merchants passed silk, gold, fruit, and glass along the Silk Road in more than one direction．They earned their living by traveling the famous Silk Road．
The Silk Road was not a simple trading network．It passed through thousands of cities and towns．It started from eastern China, across Central Asia and the Middle East, and ended in the Mediterranean Sea．It was used from about 200 B．C．to about 1300 A．D．, when sea travel offered new routes（路线）．It was sometimes called the world’s longest highway．However, the Silk Road was made up of many routes, not one smooth path．They passed through what are now 18 countries．The routes crossed mountains and deserts and had many dangers of hot sun, deep snow and even battles．Only experienced traders could return safe．
The Silk Road got its name from its most prized product．Silk could be used like money to pay taxes or buy goods．But the traders carried more than just silk．Gold, silver, and glass from Europe were much found in the Middle East and Asia．Horses traded from other areas changed farming practices in China．Indian merchants traded salt and other valuable goods．Chinese merchants traded paper, which produced an immediate effect on the West．Apples traveled from central Asia to Rome．The Chinese had learned to graft（嫁接） different trees together to make new kinds of fruit．They passed this science on to others, including the Romans．The Romans used grafting to grow the apple．Trading along the Silk Road led to world-wide business 2,000 years before the World Wide Web．
The people along the Silk Road did not share just goods．They also shared their beliefs．The Silk Road provided pathways for learning, diplomacy（外交）, and religion （宗教）．It’s probable that traders along the Silk Road needed ．
| A．to remember the entire trade route | B．to know the making of products |
| C．to receive certain special training | D．to deal with a lot of difficulties |
The Silk Road became less important because．
| A．it was made up of different routes | B．silk trading became less popular |
| C．sea travel provided easier routes | D．people needed fewer foreign goods |
What does the underlined part in Paragraph 3 refer to?
| A．Silk． | B．A trading network． |
| C．The world’s longest highway． | D．Goods．k.s.5.u |
Did you know that women’s brains are smaller than men’s? The average women’s brain weighs 10% less than men’s．Since research has shown that the bigger the brain, the cleverer the animal, men must be more intelligent（聪明的） than women．Right? Wrong．Men and women always score similarly on intelligence tests, despite the difference in brain size．Why? After years of study, researchers have concluded that it’s what’s inside that matters, not just the size of the brain．The brain consists of “grey matter” and “white matter”．While men have more of the latter, the amount of “thinking” brain is almost exactly the same in both sexes．
It has been suggested that smaller brain appears to work faster, perhaps because the two sides of the brain are better connected in women．This means that little girls tend to learn to speak earlier, and that women can understand sorts of information from different sources at the same time．When it comes to talking to the boss on the phone, cooking dinner and keeping an eye on the baby all at the same time, it’s women who come out on top every time．
There are other important differences between two sexes．As white matter is the key to spatial（空间的） tasks, men know better where things are in relation to other things．“A great footballer always knows where he is in relation to the other players, and he knows where to go,” says one researcher．That may explain one of life’s great mysteries: why men refuse to ask for directions…and women often need to!
The differences begin when fetuses（胎儿） are about nine weeks old, which can be seen in the action of children as young as one．A boy would try to climb a barrier （障碍物） before him or push it down while a girl would attract help from others．These brain differences also explain the fact that more men take up jobs that require good spatial skills, while more women speech skills．It may all go back to our ancestors（祖先）, among whom women needed speech skills to take care of their babies and men needed spatial skills to hunt, according to one research．
If all this disappoints you, it shouldn’t．“The brain changes throughout our lives according to what we do with it．” says a biologist．The passage mainly tells us ________．
| A．the difference between men’s and women’s brains |
| B．the changes in brain throughout our lives |
| C．that men are better at spatial tasks |
| D．that brain differences are related to our ancestors |
Which of the following is true according to the first paragraph?
| A．Women’s brain is 10% less than men’s |
| B．Grey matter plays the same role as white matter．k.s.5.u |
| C．Grey matter controls thinking in the brain． |
| D．Both sexes have the same amount of white matter． |
What can we infer from the second and third paragraphs?
| A．Women prefer doing many things at a time． |
| B．Men do better dealing with one job at a time． |
| C．Women do not need to tell directions． |
| D．Men have weaker spatial abilities． |
What is the writer’s attitude in writing this passage?
| A．Defensive． | B．Persuasive． | C．Supportive． | D．Objective． |
Among various programs, TV talk shows have covered every inch of space on daytime television. And anyone who watches them regularly knows that each one is different in style. But no two shows are more opposite in content, while at the same time standing out above the rest, than the Jerry Springer and Oprah Winfrey shows.Jerry Springer could easily be considered the king of "rubbish talk". The topics on his show are as surprising as can be. For example, the show takes the ever-common talk show titles of love, sex, cheating, and hate, to a different level. Clearly, the Jerry Springer show is about the dark side of society, yet people are willing to eat up the troubles of other people's lives.
Like Jerry Springer, Oprah Winfrey takes the TV talk show to its top. But Oprah goes in the opposite direction. The show is mainly about the improvement of society and different quality of life. Contents are from teaching your children lessons, managing your work week, to getting to know your neighbors.
Compared to Oprah, the Jerry Springer show looks like poisonous waste being poured into society. Jerry ends every show with a "final word". He makes a small speech about the entire idea of the show. Hopefully, this is the part where most people will learn something very valuable.
Clean as it is, the Oprah show is not for everyone. The show's main audience are middle-class Americans. Most of the people have the time, money and ability to deal with life's tough problems. Jerry Springer, on the other hand, has more of a connection with the young adults of society. These are 18-to 21year-olds whose main troubles in life include love, relationship, sex, money and drug. They are the ones who see some value and lessons to be learned through the show's exploitation.Compared with other TV talk shows, both the Jerry Springer and the Oprah Winfrey shows are____.
| A．more interesting | B．unusually poplar | C．more detailed | D．more formal |
Though the social problems Jerry Springer talks about appear unpleasant, people who watch the shows ______.
| A．show disbelief in them | B．are ready to face up to them |
| C．remain cold to them | D．are willing to get away from them |
Which of the following is likely to be a topic of the Oprah Winfrey show?
| A．A new type of robot. | B．National hatred. |
| C．Family income planning. | D．Street accident. |
We can learn from the passage that the two talk shows ____.
| A．have become the only ones of its kind | B．exploit the weaknesses in human nature |
| C．appear at different times of the day | D．attract different people |
What is the advantage of the Jerry Springer show?
| A．The show exposes the dark sides of society. | B．The show pours poisonous waste into society. |
| C．Jerry sums up the whole idea of the show. | D．Jerry talks abou the improvement of society. |
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.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 |
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 |
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 |
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 |
The writer’s attitude towards the discovery is ________.
| A．neutral | B．negative | C．positive | D．indifferent |