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Older Volcanic Eruptions
Volcanoes were more destructive in ancient history, not because they were bigger, but because the carbon dioxide they released wiped out life with greater ease.
Paul Wignall from the UniversityofLeedswas investigating the link between volcanic eruptions and mass extinctions. Not all volcanic eruptions killed off large numbers of animals, but all the mass extinctions over the past 300 million years coincided with huge formations of volcanic rock. To his surprise, the older the massive volcanic eruptions were, the more damage they seemed to do. He calculated the "killing efficiency" for these volcanoes by comparing the proportion of life they killed off with the volume of lava that they produced. He found that size for size, older eruptions were at least 10 times as effective at wiping out life as their more recent rivals.
The Permian extinction 1, for example, which happened 250 million years ago, is marked by floods of volcanic rock in Siberia that cover an area roughly the size of western Europe. Those volcanoes are thought to have pumped out about 10 gigatonnes of carbon as carbon dioxide. The global warming that followed wiped out 80 per cent of all marine genera at the time, and it took 5 million years for the planet to recover. Yet 60 million years ago, there was another huge amount of volcanic activity and global warming but no mass extinction. Some animals did disappear but things returned to normal within ten thousands of years. "The most recent ones hardly have an effect at all," Wignall says. He ignored the extinction which wiped out the dinosaurs 65 million years ago, because many scientists believe it was primarily caused by the impact of an asteroid. He thinks that older volcanoes had more killing power because more recent life forms were better adapted to dealing with increased levels of CO2.
Vincent Courtillot, director of the Paris Geophysical Institute inFrance, says that Wignall"s idea is provocative. But he says it is incredibly hard to do these sorts of calculations. He points out that the killing power of volcanic eruptions depends on how long they lasted. And it is impossible to tell whether the huge blasts lasted for thousands or millions of years. He also adds that it is difficult to estimate how much lava prehistoric volcanoes produced, and that lava volume may not necessarily correspond to carbon dioxide emissions.
词汇：
dioxide [daɪˈɒksaɪd] n. 二氧化物
lava ["lɑ:və] n. 熔岩
Permian [ˈpə:miən] adj. 二叠纪
gigaton ["dʒɪgətʌn] n. 十亿吨梯恩梯
genera ["dʒenərə] n. 种类
dinosaurs ["daɪnəsɔ:z] n. 恐龙
asteroid [ˈæstərɔɪd] n. 小行星
注释：
1.The Permian extinction:二叠纪物种灭绝
Why did older volcanic eruptions do more damage than more recent ones？
A:Because they killed off life more easily. B:Because they were brighter. C:Because they were larger. D:Because they were hotter.
Text 3
Recently, a possible alternative way of producing paper has been suggested by agriculturalists and environmentalists: a plant called hemp.
Hemp has been cultivated by many cultures for thousands of years. It produces fiber, which can be made into paper, fuel, oils, textiles, food, and rope. For centuries, it was essential to the economies of many countries because it was used to make the ropes and cables used on sailing ships; colonial expansion and the establishment of a world wide trading network would not have been feasible without hemp. Nowadays, ships’ cables are usually made from wire or synthetic fibers, but scientists are now suggesting that the cultivation of hemp should be revived for the production of paper and pulp. According to its proponents, four times as much paper can be produced from land using hemp rather than trees, and many environmentalists believe that the large-scale cultivation of hemp could reduce the pressure on world’ s forests.
However, there is a problem: hemp is illegal in many countries of the world. This plant, so useful for fiber, rope, oil, fuel and textiles, is a species of cannabis(大麻), related to the plant from which marijuana is produced. In the late 1930s, a movement to ban the drug marijuana began to gather froce, resulting in the eventual banning of the cultivation not only of the plant used to produce the drug, but also of the commercial producing--producing hemp plant. Although both George Washington and Thomas Jefferson grew hemp in large quantities on their own land, any American growing the plant today would soon find himself in prison -- despite the fact that marijuana cannot be produced from the hemp plant, since it contains almost no THC (the active ingredient in the drug).
In recent years, two major movements for legalization have been gathering strength. One group of activists believes that ALL cannabis should be legal -- both the hemp plant and the marijuana plant -- and that the use of the drug marijuana should not be an offense. They argue that marijuana is not dangerous or addictive, and that it is used by large numbers of people who are not criminals but productive members of society. They also point out that marijuana is less toxic than alcohol or tobacco. The other legalization movement is concerned only with the hemp plant used to produce producing; this group wants to make it legal to cultivate the plant and sell the fiber for paper and pulp production. This second group has had a major triumph recently: in 1997, Canada legalized the farming of hemp for fiber. For the first time since 1938, hundreds of farmers are planting this crop, and soon we can expect to see pulp and paper produced from this new source.
A:It is cheaper to grow hemp than to cut down trees. B:More paper can be produced from the same area of land. C:Hemp produces higher quality paper. D:It is easier to find hemp than to find trees.
Way do agriculturalists think that hemp would be better for paper production than trees
A:It is cheaper to grow hemp than to cut down trees. B:More paper can be produced from the same area of land. C:Hemp produces higher quality paper. D:It is easier to find hemp than to find trees.
Passage Four 4
It was Monday, Mrs. Smith’s dog was hungry, but there was not any meat in the house.
Considering that there was no better way, Mrs. Smith took a piece of paper, and wrote the following words on it, "Give my dog half a pound of meat." Then she gave the paper to her dog and said gently, "Take this to the butcher (卖肉者) , and he’s going to give you your lunch today."
Holding the piece of paper in its mouth, the dog ran to the butcher’s shop. It gave the paper to the butcher. The butcher read it carefully, recognized that it was really the lady’s handwriting and presently did as he was asked to. The dog was very happy, and ate the meat up immediately.
At midday (正午), the dog came to the shop again. It gave the butcher a piece of paper again. After reading it, he gave it half a pound of meat once more.
The next day, the dog came again exactly at midday. And as usual it brought a piece of paper in. the mouth. This time, the butcher did not take a look at the paper, and gave the dog its meat, for he had regarded the dog as one of his customers.
But, the dog came again at four o’clock. And the same thing happened once again. To the butcher’s more surprise, it came for the third time at six o’clock, and brought with it a third piece of paper. The butcher felt a bit puzzled. He said to himself, "This is a small dog. Why does Mrs. Smith give it so much meat to eat today"
Looking at the piece’ of paper, he found that there were not any words on it!
A:the butcher found himself cheated by the smart animal B:the dog was clever enough to write on the paper C:the dog dared not go to tile butcher's any more D:the butcher was told not to give any meat to the dog
Passage Three
Newspapers, along with reporting the news, instruct, entertain, and give opinions. An important way for reading a large, big-city newspaper is knowing how to take it apart. Can you find these separate sections: world news, national and local news, sports, business, entertainment, opinions, classified ads Does your paper have other sections
News stories give facts, not the author’s opinions. Editorials do the opposite; you can expect an editorial to take sides. Some newspaper editorials have a by-line with the author’s name, but many newspapers have unsigned editorials. These reflect the opinions of the publisher or editor.
You can be a better reader if you know what to expect in a newspaper. For example, you can expect headlines to omit unnecessary words. You can expect to find the most important facts in the lead paragraph (the first paragraph) of a news story. You can expect important news items to be on the front page. You can expect less important items to be on the inside pages.
Most of all, the more you know about current news, the more you will understand what is in the newspaper; important stories are generally presented one day and followed up on following days. So, an important way for reading newspapers is reading one frequently.
A:to read it section be section B:to do some paper-cutting C:to find separate sections and read accordingly D:to predict what is inside the newspaper
Passage Four
It was Monday, Mrs. Smith’s dog was hungry, but there was not any meat in the house.
Considering that there was no better way, Mrs. Smith took a piece of paper, and wrote the following words on it, "Give my dog half a pound of meat." Then she gave the paper to her dog and said gently, "Take this to the butcher (卖肉者) , and he’s going to give you your lunch today."
Holding the piece of paper in its mouth, the dog ran to the butcher’s shop. It gave the paper to the butcher. The butcher read it carefully, recognized that it was really the lady’s handwriting and presently did as he was asked to. The dog was very happy, and ate the meat up immediately.
At midday (正午), the dog came to the shop again. It gave the butcher a piece of paper again. After reading it, he gave it half a pound of meat once more.
The next day, the dog came again exactly at midday. And as usual it brought a piece of paper in. the mouth. This time, the butcher did not take a look at the paper, and gave the dog its meat, for he had regarded the dog as one of his customers.
But, the dog came again at four o’clock. And the same thing happened once again. To the butcher’s more surprise, it came for the third time at six o’clock, and brought with it a third piece of paper. The butcher felt a bit puzzled. He said to himself, "This is a small dog. Why does Mrs. Smith give it so much meat to eat today"
Looking at the piece’ of paper, he found that there were not any words on it!
A:the butcher found himself cheated by the smart animal B:the dog was clever enough to write on the paper C:the dog dared not go to tile butcher's any more D:the butcher was told not to give any meat to the dog
Passage Four It was Monday, Mrs. Smith’s dog was hungry, but there was not any meat in the house. Considering that there was no better way, Mrs. Smith took a piece of paper, and wrote the following words on it, "Give my dog half a pound of meat." Then she gave the paper to her dog and said gently, "Take this to the butcher (卖肉者) , and he’s going to give you your lunch today." Holding the piece of paper in its mouth, the dog ran to the butcher’s shop. It gave the paper to the butcher. The butcher read it carefully, recognized that it was really the lady’s handwriting and presently did as he was asked to. The dog was very happy, and ate the meat up immediately. At midday (正午), the dog came to the shop again. It gave the butcher a piece of paper again. After reading it, he gave it half a pound of meat once more. The next day, the dog came again exactly at midday. And as usual it brought a piece of paper in. the mouth. This time, the butcher did not take a look at the paper, and gave the dog its meat, for he had regarded the dog as one of his customers. But, the dog came again at four o’clock. And the same thing happened once again. To the butcher’s more surprise, it came for the third time at six o’clock, and brought with it a third piece of paper. The butcher felt a bit puzzled. He said to himself, "This is a small dog. Why does Mrs. Smith give it so much meat to eat today" Looking at the piece’ of paper, he found that there were not any words on it!
At the end of the story, you'll find that （）A:the butcher found himself cheated by the smart animal B:the dog was clever enough to write on the paper C:the dog dared not go to tile butcher's any more D:the butcher was told not to give any meat to the dog
下面有3篇短文，每篇短文后有5道题。请根据短文内容，为每题定1个最佳选项。
{{B}}第一篇{{/B}}
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How to Start a Small Business in the
US ? ?People from other countries often take America as the "land of opportunity". Americans, too, believe that the country gives no end of chances to those who want to open their own businesses. Today, many Americans are still trying hard to become small business people, although only one out of two remains in operation after the first two years. ? ?Many people start their small businesses for the wrong reasons. They want to get away from the paper work of their present jobs, or to exchange the responsibility of their present jobs for free life styles. But more, not less, paper work and responsibility come with ownership of a small business. ? ?Thomas is the owner of the news magazine Mother Earth, which is now quite successful. He says that he had to work sixty hours without stopping when he was trying to bring out the first issue. ? ?Thomas had waited for years after he came up with the idea for Mother Earth. During that time, he collected as much information as he could about his business. He borrowed books from the library, talked to successful people in the field, and began planning carefully the amount of money and the kinds and numbers of supplies he would need. When he finally opened with a capital of $ 1,500 ,he set up his office in the kitchen and his printing press in the garage. Owing to his devotion(投入)to business, his talent, and his skill in management, Mother Earth now has a circulation(发行量) of 300,000. ? ?Not all small businesses are doing as fine as Mother Earth as 50% of the 450,000 that start in America every year fail. Still, 95% of businesses in the US can be called "small". Altogether these businesses amount to 40% of America’s gross national product(国民生产总值). |
A:do heavy work or earn more money B:do less paper work or take less responsibility C:do more paper work or take less responsibility D:do light work or live quiet lives
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