阅读下列短文，从每题所给的四个选项 （A 、B 、C  和 D ）中，选出最佳选项。

    A recent announcement by scientists that they have successfully cloned the first human embryo(胚胎) has caused much debate and has shocked many people around the world. On the one hand, some scientists point out that if you clone an embryo, you can produce valuable tissues(组织) and organs that could be used to save human lives. On the other hand, many people, including some scientists, disagree and fear that if mankind interferes with (干涉) nature in this way, they may be on their way to producing a real-life Frankenstein's monster.

Cloning is producing an exact copy of a plant or an animal using its cells. The first mammal to be cloned successfully from an adult cell was Dolly—the sheep. She was born in 1996 and died in early 2003, at a much younger age than normal. When she was born, many people were angry because they thought cloning would create more diseases in the animal world. However, in general the scientists were praised for their wonderful scientific breakthrough.

    The Scottish scientist who created Dolly, Ian Wilmut, is shocked that some scientists are now considering cloning human beings. Although he researches cloning, he has never thought of creating copies of humans. Instead, he thinks the scientists should concentrate on creating new tissues and organs that could eventually be used to cure diseases like cancer. However, some people consider that cloning human embryos with the intention of destroying them shows no respect for human lives.

    While cloning human embryos is illegal in many countries, some scientists are already pushing ahead with the research so as to deliver a cloned human baby. Severino Antinori, an Italian doctor, is one of the leaders in this field of research. He has declared that he wants to be the first to clone a human being.

In China, scientists have focused their efforts on cloning animals, as well as stem cells to be used in medical research. China has succeeded in producing clones of cows and goats, and continues to research ways in which cloning can benefit mankind.

    For centuries, people wondered how big the Earth was. Unfortunately, although the Earth was flat, no one was able to figure out its size. Gradually, however, people began to realize that the Earth was really round.

    Then, in the third century BC(2,300 years ago), a Greek man named Eratosthenes had an idea. Eratosthenes was sure that the Earth was a sphere. He used the sun and geometry(几何学) to figure out the size of the Earth. He calculated that the circumference(圆周) of the Earth was 28,600 miles(46,000 kilometers). The true size of the Earth is 25,000 miles(40,000 kilometers).

    Eratosthenes' measurement was wrong, but it was very close to the truth.

    For many centuries after Eratoshenes lived, people made maps of the Earth. However, they did not know very much about the world outside of Europe, Asia, and North Africa. Mapmakers could not draw accurate maps of the Earth until people began traveling around the world in the fifteenth century, mapping small areas each time. In the eighteenth and nineteenth centuries, people began making correct maps of countries, but the first accurate maps of the world were not made until the 1890s.

    Maps today are reliable(可依靠的), inexpensive, and easy to understand. People depend on maps every day. What would our lives be like without them?

    Mark Twain was a great writer. He was from the USA. He was born in 1835. He was also a famous speaker. He was famous for his sense of humor. Many people liked to listen to him talk because he liked to tell some interesting stories to make people laugh all the time.

    One day Mark Twain was going to a small town because of his writing. Before he was going to leave, one of his friends said to him that there were always a lot of mosquitoes in the town and told him that he'd better not go there. Mark Twain waved (摇动) his hand and said, ＂It doesn't matter. The mosquitoes are not relatives of mine. I don't think they will come to visit me.＂

    After he arrived at the town, Mark Twain stayed in a small hotel near the station. He went into his room, but when he was just about to have a rest, quite a few mosquitoes flew about him. The waiters felt very sorry about that. ＂I'm very sorry, Mr. Mark Twain. There are too many mosquitoes in our town.＂ One of them said to him.

    Mark Twain, however, made a joke, saying to the waiter, ＂The mosquitoes are very clever. They know my room number. They didn't come into the wrong room.＂ What he said made all the people present laugh heartily.

    But that night Mark Twain slept well. Do you know why? That was because all the waiters in the hotel were driving the mosquitoes away for him during the whole night.

    Colorado officials will stick to a plan to kill some mountain lions and bears to support the state's dropping mule deer (长耳鹿) population.

    Wednesday's vote permits organizations to kill up to 25 black bears and 15 mountain lions per year in the central and western parts of the state. The project will run for three years, to be followed by a six-year study of how deer populations respond to fewer predators(捕食者).

    The population of Colorado's mule deer has suffered a puzzling, years-long drop to about 450,000, which state officials said was about 110,000 fewer than there should be. A 2014 state study tied it to seven causes, including predators, whose number has greatly increased in recent years.

    Some experts, however, said the state should focus first on the human-led destruction(破坏) of mule deer habitat(栖息地). “The drop of the mule deer population is obviously not a simple problem with simple causes,” Brian Kurzel, director of the National Wildlife Federation, said. “By far, the greatest problem—the one that I think deserves the most attention in any science-based study—is habitat quantity and quality.”

    Kurzel pointed out that the U.S Bureau of Land Management recently agreed to create 15,000 new oil and gas wells somewhere in western Cororado, which was often called “the mule-deer factory”. There, the number of mule deer has fallen to about 30,000 from more than 100,000 in the early 1980s. Though state officials have known oil and gas development affects the population of mule deer, they didn't go against the plan.

    Other causes like building highways, population growth and human activities are also curbing the mule deer population, according to the study.

    State Parks and Wildlife officials don't necessarily disagree. They started a $4.5 million program as a way to gather research for later decisions.

    Researchers found that compared with young people who spent much of their free time in front of TV sets, those who were physically active often had higher self-respect, better grades and were less likely to have risky behavior like taking drugs, smoking, or drinking. The findings, based on a national survey of nearly 12, 000 middle and high school students, were published in a journal（期刊）.

    “Across the board, children who engaged in any kind of activity were better off than kids who watched a lot of TV,” said study co-author(合著者) professor Penny Gordon Larsen of the University of North Carolina.

    Other studies have linked certain content of television programs, such as violence and sex, to children's behavior. But beyond this issue, Gordon Larsen said that kids who spend hours watching TV” miss opportunities” to develop skills, learn teamwork and have other experiences that their more active peers(同辈) benefit(受益) from

    That doesn't mean, however, that kids have to be on the football team. The study found that some activities like skating and skateboard(滑板)——which adults sometimes frown upon——were also related to better self-respect and less risk-taking.

    That skaters were better behaved than TV-watchers might come as a surprise to some adults who consider these teens to be bad, according to Gordon Larsen. Skateboarding is forbidden in many public areas, and some communities(社区) disagree to build skating parks. But if kids who like to skate have nowhere to do it, “ it's a shame,” said Gordon Larsen.

    Not only should parents encourage their kids to engage（参与） in the physical activities they enjoy, she said, but schools and communities should also do more to create opportunities for children to be active.

    I start every summer with the best of intentions: to attack one big book from the past, a classic that I was supposed to have read when young and ambitious. Often the pairings of books and settings have been purely unthinking: "Moby Dick" on a three-day cross-country train trip: “The Magic Mountain” in a New England beachside cottage with no locks on the doors, no telephones or televisions in the rooms, and little to do beyond row on the salt pond. Attempting "The Man Without Qualities" on a return to Hawaii, my hometown, however, was less fruitful: I made it through one and a quarter volumes (册), then decided that I'd got the point and went swimming instead.

    But this summer I find myself at a loss. I'm not quite interested in Balzac, say, or “Tristram Shandy.” There's always War and Peace, which I've covered some distance several times, only to get bogged down in the "War" part, set it aside for a while, and realize that I have to start over from the beginning again, having forgotten everyone's name and social rank. How appealing to simply fall back on a favorite once more into “The Waves” or “Justine,” which feels almost like cheating, too exciting and too much fun to properly belong in serious literature.

    And then there's Stendhal's “The Red and the Black,” which happens to be the name of my favorite cocktail of the summer, created by Michael Cecconi at Savoy and BackForty. It is easy to drink, and knocking back three or four seems like such a delightful idea. Cecconi's theory: "I take whatever's fresh at the green market and turn it into liquid." The result is a pure shot of afternoon in the park, making one feel cheerful and peaceful all at once, lying on uncut grass with eyes shut, sun beating through the lids…