My family is American, and has been for generation...

A、Members of my family have used this radio to listen to the news for generation.

B、Members of my family have used this radio to listen to the news of generations.

C、Members of my family have used this radio to listen to the news for generations.

Scientists are hoping to eliminate malaria (疟疾) by developing a genetically modified mosquito that cannot transmit the disease. Malaria has long troubled the populations of South America, Africa, and Asia, where mosquito bites infect up to 500 million people a year with this serious and sometimes fatal parasitic blood disease. For generations, scientists have been trying to eliminate malaria by developing new drugs and using pesticides (杀虫剂) to wipe out local mosquito populations. But these measure aren't working--and some scientists, like Greg Lanzaro, say that because of drug resistance and population changes, malaria is actually more prevalent now than it was 20 years ago. Lanzaro says he has a better way to stop the spread of malaria: genetically modifying mosquitoes so they are unable to carry the disease.

Lanzaro and his. colleagues are planning a multi-year project to produce malaria-resistant mosquitoes--and he thinks they can do it within five years. "We can get foreign genes into mosquitoes and they go where they're supposed to go," Lanzaro says, pointing out that scientists have already succeeded in genetically engineering mosquitoes that cannot transmit malaria to birds and mice. And, he says, scientists are quickly making progress on genes that block transmission of the disease to humans as well.

The most difficult part scientifically, Lanzaro says, is figuring out how to get the lab-engineered mosquitoes to spread their genes into natural populations. After all, he points out, it's useless to engineer mosquitoes in the lab that can't transmit malaria when there are millions out in the wild that can. To solve this problem, Lanzaro wants to load up a mobile piece of DNA with the malaria-resistant gene, and then insert it into a group of mosquito embryos. The malaria-resistant gene would be integrated directly into the mosquitoes' DNA, making it impossible for those mosquitoes to transmit the parasite that causes malaria. In this way a small group of lab-raised mosquitoes could be released into the wild, and by interbreeding with wild mosquitoes, eventually transmit the beneficial gene to the entire population.

One reason for malaria to be widespread now is that ______

A．more people have moved to malaria-infected areas

B．mosquitoes have become resistant to pesticides

C．genetically modified mosquitoes still transmit the disease

D．mosquitoes bite as many as 500 million people a year

Web Du Bois was born a free man in his small village of Great Barington, Massachusetts, three years after the Civil War. For generations, the Du Bois family had been an accepted part of the community since before his great-grandfather had fought in the American Revolution.

Early on, Du Bois was given an awareness of his African-heritage, through the ancient songs his grandmother taught him. This awareness set him apart from his New England community, with an ancestry shrouded in mystery, in sharp contrast to the precisely accounted history of the Western world. This difference would be the foundation for his desire to change the way African-Americans co-existed in America.

As a student, Du Bois was considered something of a prodigy who excelled beyond the capabilities of his white peers. He found work as a correspondent for New York newspapers, and slowly began to realize the inhibitions of social boundaries he was expected to observe every step of the way. When racism tried to take his pride and dignity, he became more determined to make sure society recognized his achievements.

Clearly, Du Bois showed great promise, and although he dreamt of attending Harvard, some influential members of his community arranged for his education at Fisk University in Nashville. His experiences at Fisk changed his life; and he discovered his fate as a leader of the black struggle to free his people from oppression. At Fisk, Du Bois became acquainted with many sons and daughters of former slaves, who felt the pain of oppression and shared his sense of cultural and spiritual tradition. In the South, he saw his people being driven to a status of little difference from slavery, and saw them terrorized at the polls. He taught school during the summers in the eastern portion of Tennessee, and saw the suffering firsthand. He then resolved to dedicate his life to fighting the terrible racial oppression that held the black people down, both economically and politically.

Du Bois's determination was rewarded with a scholarship to Harvard, where he began the first scientific sociological studies in the United States. He felt that through science, he could dispel the irrational prejudices and ignorance that prevented racial equality. He went on to create great advancements in the study of race relations, but oppression continued with segregation laws, lynching, and terror tactics on the rise. Du Bois then formed the Niagara Movement, and in 1909, was a vital part in establishing the National Association for the Advancement of Colored People. He was also the editor of the NAACP magazine The Crisis from 1910 to 1934. In this stage of his life, he encouraged direct assaults on the legal, political, and economic system, which he felt blossomed out of the exploitation of the poor and powerless black community.

He became the most important black protest leader of the first half of the 20th century. His views clashed with Booker T. Washington, who felt that the black people of America had to simply accept discrimination, and hope to eventually earn respect and equality through hard work and success. Du Bois wrote The Souls of Black Folk in 1903, criticizing Booker, claiming that his ideas would lead to a perpetuation of oppression instead of freeing the black people from it. Du Bois's criticism lead to a branching out of the black civil rights movement, Booker's conservative followers, and a radical following of his critics.

Du Bois had established the Black Nationalism that was the inspiration for all black empowerment throughout the civil rights movement, but had begun during the progressive era. Although the movement that germinated from his ideas may have taken on a more violent form, Web Du Bois felt strongly that every human being could shape their own destinies with determination and hard work. Fie inspired hope by declaring that progress would come with the success of the small struggles for a be

A．the Civil War had eliminated racial discrimination in the U.S.

B．his grandmother could recite the history of the western world

C．Du Bois was considered something of a prodigy and very promising

D．his great-grandfather had fought in the American war of independence

Americans should stop acting surprised that these shooting happen in "nicer" neighborhoods.That's the only place they happen.None of the recent school massacres took place at an inner-city campus; they all occurred in smaller towns or suburbs.These killers haven't been from impoverished or extremely violent families.They don't appear to have been picked on(挨骂受罚) any worse than kids have been for generations.They chose alienation and destruction,and they found the tools to carry out their hate-filled plan.

Do not blame schools for these massacres.Schools simply take what they are sent.Question the killers' parents.The parents are supposed to teach their children respect and empathy for others' lives.Parents should help their offspring learn to handle taunt or conflict without resorting to violence.

All concerned adults should take a youth's threat to shoot someone as seriously as airport security guards take jokes about bombs.Students must be encouraged to tell teachers if a classmate threatens or jokes about violence.Administrators at schools around the country need to emphasize they will take such reports seriously,and that they will not identify any student who comes forward with such a report.

More gun regulations probably won't stop these shootings,but gun owners and sellers must take more responsibility for keeping weapons away from young people.Gun owners should keep their guns unloaded,locked up and hidden away.Most car owners don't leave their keys in the car even when they park in their own garage; gun owners should be at least as careful with weapons.

The federal government can't solve this problem.Schools alone can't solve it.More guns won't solve it.Americans must consciously create a culture that makes violence unacceptable.Parents need to stop allowing their children's minds to be polluted with violence.News media need to show more restraint and thought about how and what they report.

The Colorado massacre is a national tragedy.More's the pity if Americans do not stop,reflect and vow to make it the last school massacre.

1.One common feature of all the recent school massacres is that ______.

A) they have all been carefully planned by hateful youngsters

B) the killers have all failed to passed their exams?

C) they all occur in places that appear to be all right

D) the killers are all from disadvantaged families

2.Children are less likely to become killers if ______.

A) their parents succeed in teaching them respect and empathy for others' lives

B) they study hard in school and get high scores?

C) teachers stop telling meaningless jokes in class

D) they follow the rules set by administrators at schools around the country

3.Who does the author think should take the main responsibility for campus shootings?

A) School authorities.

B) The federal government.

C) News media.

D) The killers' parents.

4.What is the most effective way to prevent school massacre from happening again?

A) Reinforcing stricter laws and regulations.

B) Introducing security guards onto campus.

C) Creating a culture that makes violence unacceptable.

D) Keeping weapons away from young people.

5.From the passage we can infer that ______.

A) there were a lot of school massacres in inner-cities 10 years ago

B) many people turn a blind eye to school massacre

C) a youth's joke about violence is often ignored by other people

D) most gun owners like to leave their guns in their cars

Part Ⅱ Reading Comprehension (Skimming and Scanning)

Directions: In this part you will have 15 minutes to go over the passage quickly and answer the questions on Answer Sheet 1. For questions 1-7, choose the best answer from the four choices marked A), B), C) and D). For questions 8-10, complete the sentences with the information given in the passage.

How Sled Dogs Work

They're physical wonders--able to endure extreme conditions for extensive periods of time while running fast and pulling more than their own weight. Sled (雪橇) dogs have been around for generations, and today they remain a large part of a dog driver's life.

In Arctic (北极的) regions, some 35 000 years ago, Eskimos' dogs bred with wolves and other dogs. Their offspring were well-adapted to the cold and snow. There's no saying exactly when someone thought to have dogs pull sleds ,but it was well before 1000 B. C. that dog sleds provided a means of transportation and a way to haul goods. In recent years, people looking for unique outings have gone on recreational trips with sled dogs. A number of companies market tourist treks via dog sled for adventure travelers.

Dogsled racing in Alaska formally began in 1908, when sled dog owners in Nome, Alaska, held the first All-Alaska Sweepstakes, a 408-mile race from Nome to Candle and back. And in 1973, the inaugural Iditarod Trail Sled Dog Race took place on a route covering more than 1 000 miles in Alaska. There are more competitions in many of the continental United States, and some take place on dry land. In addition to endurance races, sled-dog events include sprint races, weight pulls (in which dogs try to pull the most weight) and freight races ( in which dogs try to pull a weighted sled the fastest).

Stamina (耐力) and Strength

Many breeds of dogs are used to pull sleds, including official American Kennel Club breeds such as the Siberian husky, Malamute and Samoyed. However, many sled dogs are of mixed breed and are called Alaska husky or Eskimo dogs. While some sled dogs may have wolf bloodlines, it's generally not desirable to have a mixture of blood between the two.

Sled dogs are bred for their speed and endurance as well as leadership qualities. They are big dogs with thick coats and wide, fiat feet. They sleep with their tails covering their noses to keep warm. Dogs that weigh around 40 to 45 pounds are the ideal size to pull sleds, but some may weigh as much as 85 pounds.

Young dogs that are enthusiastic runners, easy-going and mentally tough are good choices for sled dogs. A dog's gender matters little and both male and female dogs are considered equally.

For racing, the most intelligent and fastest dogs are picked to be lead dogs and run in the front of the pack. Behind them run swing dogs, whose job is to direct the team around turns and curves. At the back of the dog team are the wheel dogs or wheelers, who are right in front of the sled and are usually the largest and strongest of the team. The rest of the dogs are known simply as team dogs.

Dogs are typically from 2 to 10 years old when they pull sleds. After they retire, they might remain with their owner at a kennel or be adopted as pets by others. Rescue groups for sled dogs take in unwanted dogs and care for them, trying to place them in loving homes.

While snowmobiles (also called snow machines), helicopters and airplanes are now often used in place of sled dogs, there are still times when dog transportation is preferred. Harsh weather conditions can make flying hazardous, and certain terrain can be more difficult for snow machines to cross than for dogs. Dogs can be more reliable than man-made machines, they're good companions to have on long treks and they can be cheaper to own than

A．Because they are raised by wolves.

B．Because they can stand most severe weather.

C．Because they are fastest runner among Arctic animals.

D．Because they can bear goods like horses do.

Excerpt 1 The process of vaccination allows the patients body to develop immunity to the virus or disease so that, if it is encountered, one can ward it off naturally.To accomplish this, a small weak or dead strain of the disease is actually injected into the patient in a controlled environment, so that his bodys immune system can learn to fight the invader properly.Information on how to penetrate the diseases defenses is transmitted to all elements of the patients immune system in a process that occurs naturally, in which genetic information is passed from cell to cell. Excerpt 2 Scientists are hoping to eliminate malaria (疟疾) by developing a genetically modified mosquito that cannot transmit the disease.Malaria has long troubled the populations of South America, Africa, and Asia, where mosquito bites infect to 500 million people a year with this serous and sometimes fatal parasitic blood disease. For generations, scientists have been trying to eliminate malaria by developing new drugs and using pesticide (杀虫剂) to wipe out local mosquito populations.But these measures arent working...and some scientists, like Greg Lanzaro, say that because of drug resistance and population changes, malaria is actually more prevalent now than it was 20 years ago. Excerpt 3 Most diseases involve the death of healthy cells—brain cells in Alzheimers, cardiaccells in heart disease, pancreatic cells in diabetes, to name a few if doctors could isolate stem cells, then direct their growth, they might be able to furnish patients with healthy replacement tissue. Excerpt 4 The prospective rewards of gene therapy are tremendous:the suppression and even prevention of inherited disease.At present, gene therapy is being directed at somatic cells, the working cells in a human body that do not pass on genes to the next generation.Therapy someday will be directed at germ cells sperm and egg cells and their precursors that do transmit genetic information to the next generation.Such therapy would remove, replace, or alter the genes that cause inherited diseases.However, mistakes in germ-line gene therapy could cause extreme deficiencies and horrendous mutations.This is an area of medical research in which work must progress with great care.No errors can be tolerated. Excerpt 5 From the health point of view we are living in a marvelous age.We are immunised from birth against many of the most dangerous diseases.A large number of once fatal illnesses can now be cured by modern drugs and surgery.It is almost certain that one day remedies will be found for the most stubborn remaining diseases. Excerpt 6 Cardiologists have pioneered the worlds first non-surgical bypass operation to turn a vein into an artery using a new technique to divert blood flow in a man with severe heart disease; the keyhole procedure, which avoids the extensive invasive surgery of a conventional bypass,will offer hope to tens of thousands of people at risk from heart attacks. Coronary heart disease, where the arteries are progressively silted up with fatty deposits, is responsible in a major industrial country like Britain for more than 160,000 deaths each year.Although major heart surgery is becoming commonplace, with more than 28,000 bypass operations in the UK annually, it is traumatic for patients and involves a long recovery period.

The phrase "ward it off naturally" (Excerpt 1) most probably means______.

A．dispose of it naturally

B．fight it off with ease

C．see to it reluctantly

D．split it up properly