When prehistoric man arrived in new parts of the world, something strong happened to the large animals; they suddenly became extinct. Smaller species survived; the large, slow-growing animals were easy game, and were quickly hunted to extinction.
Now something similar could be happening in the oceans. That the seas are being over-fished has been known for years and researchers such as Ransom Myers and Boris Worm have shown how fast things are changing. They have looked at half a century of data from fisheries around the world. Their methods do not attempt to estimate the actual biomass (the amount of living biological matter) of fish species in particular parts of the ocean, but rather changes in that biomass over time. According to their latest paper published in Nature, the biomass of large predators (animals that kill and eat other animals) inanes fishery is reduced on average by 80% within 15 years of the start of exploitation. In some long-fished areas, it has halved again since then.
Dr. Worm acknowledges that these figures are conservative (保守的). One reason for this is that fishing technology has improved. Today’s vessels can find their prey using satellites and sonar, which were not available 50 years ago. That means a higher proportion of what is in the sea is being caught, so the real difference between present and past is likely to be worse than the one recorded by changes in catch sizes. In the early days, too, longlines would have been more saturated with fish. Some individuals would therefore not have been caught, since baited hooks would have been available to trap them, leading to an underestimate of fish stocks in the past. Furthermore, in the early days of longline fishing, a lot of fish were lost to sharks after they had been hooked. That is no longer a problem, because there are fewer sharks around noise.
Dr. Myers and Dr. Worm argue that their work gives a correct baseline, which future management efforts must take into account. They believe the date support an idea current among marine biologists, that of the “shifting baseline”. The notion is that people have failed to detect the massive changes which have happened in the ocean because they have been looking back only a relatively short time into the past. That matters because theory suggests that the maximum sustainable yield that can be cropped from a fishery comes when the biomass of a target species is about 50% of its original levels. Most fisheries are well below that, which is a bad way to do business.
【小题1】The aim of the extinction of large prehistoric animals is to suggest that _______.
| A．large animal were not easy to survive in the changing environment |
| B．small species survived as large animals disappeared |
| C．large sea animals may face the same threat today. |
| D．Slow-growing fish outlive fast-growing ones |
| A．the stock of large predators in some old fisheries has reduced by 90% |
| B．there are only half as many fisheries are there were 15 years ago |
| C．the catch sizes in new fisheries are only 20% of the original amount |
| D．the number of larger predators dropped faster in new fisheries than in the old |
| A．fishing technology has improved rapidly |
| B．then catch-sizes are actually smaller then recorded |
| C．the marine biomass has suffered a greater loss |
| D．the date collected so far are out of date. |
| A．people should look for a baseline that can’t work for a longer time |
| B．fisheries should keep the yield below 50% of the biomass |
| C．the ocean biomass should restore its original level. |
| D．people should adjust the fishing baseline to changing situation. |
| A．management efficiency |
| B．biomass level |
| C．catch-size limits |
| D．technological application. |
【小题1】C
【小题2】A
【小题3】C
【小题4】D
【小题5】B
解析试题分析：文章讲述了研究人员现在指出海洋中由于过度捕捞，鱼类正在减少，说明了鱼类正在减少原因及呼吁改变捕鱼的底线来改变现在的状况。
【小题1】推断题。从文章第一自然段和第二自然段的描写中，我们可知大型史前动物的灭绝的目的是为了表明如今海洋中的大型生物可能也同样遭受着威胁，故选C
【小题2】推断题。从文章the biomass of large predators (animals that kill and eat other animals) inanes fishery is reduced on average by 80% within 15 years of the start of exploitation. In some long-fished areas, it has halved again since then. 可知，在一些老的渔场，大型捕食动物的储藏量已经减少了90%，文章提到的是平均80%，所以可知A正确。
【小题3】细节题。从文One reason for this is that fishing technology has improved.Today’s vessels can find their prey using satellites and sonar,可知，这些数字之所以是保守估计，是因为现代科学技术的进步，给捕鱼带来带来了方便，海洋生物已经遭受了更大的破坏，故选C
【小题4】推断题。从文章Dr. Myers and Dr. Worm argue that their work gives a correct baseline, which future management efforts must take into account. 及最后可知，现在绝大多数的渔场的鱼的数量只是以前的一半，甚至更少，所以人们应该调整捕鱼的基线来改变现在状态，故选D
【小题5】推断题。文章整个文段都在围绕"海洋生物总量"这个话题展开的，文中多次出现了"biomass"这个词，故选B
考点：科普类说明文
点评：本文较难，取自于2006年考研的题目。对于此类科普类文章对于学生来说，很难把握作者写作的主要意图和言外之意。那么在解答的过程中就必须结合题目中的选项，仔细的来推敲文章所表达的意思，对于一下子无法解决的问题，可以待所有题目解答完后，再来仔细的作答。
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一线名师口算应用题天天练一本全系列答案科目：高中英语 来源： 题型：阅读理解
I arrived at my mother’s home for our Monday family dinner. The smells of food flew over from the kitchen. Mother was pulling out quilt(被子)after quilt from the boxes, proudly showing me their beauties. She was preparing for a quilt show at the Elmhurst Church. When we began to fold and put them back into the boxes, I noticed something at the bottom of one box. I pulled it out. “What is this?” I asked.
“Oh?” Mom said, “That’s Mama’s quilt.”
I spread the quilt. It looked at if a group of school children had pieced it together; irregular designs, childish pictures, a crooked line on the right.
“Grandmother made this?” I said, surprised. My grandmother was a master at making quilts. This certainly didn’t look like any of the quilts she had made.
“Yes, right before she died. I brought it home with me last year and made some changes,” she said. “I’m still working on it. See, this is what I’ve done so far.”
I looked at it more closely. She had made straight a crooked line. At the center of the quilt, she had stitched(缝) a piece of cloth with these words: “My mother made many quilts. She didn’t get all lines straight. But I think this is beautiful. I want to see it finished. Her last quilt.”
“Ooh, this is so nice, Mom,” I said. It occurred to me that by completing my grandmother’s quilt, my mother was honoring her own mother. I realized, too, that I held in my hands a family treasure. It started with the loving hands of one woman, and continued with the loving hands of another.
Why did the author go to mother’s home?
A. To see her mother’s quilts. B. To help prepare for a show.
C. To get together for the family dinner. D. To discuss her grandmother’s life.
The author was surprised because .
A. the quilt looked very strange. B. her grandmother liked the quilt.
C. the quilt was the best she had seen. D. her mother had made some changes
The underlined wood “crooked” in the passage most probably means .
A. unfinished B. broken C. bent D. unusual
Which of the following would be the best title for the passage?
A. A Quilt Show B. Mother’s Home C. A Monday Dinner D. Grandmother’s Quilt
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——It started ____ the night.
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— When_______, I will let you know.
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B. will he come; he comes
C. does he come; he will come
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I travel a lot, and I find out different “styles” of directions every time I ask “How can I get to the post office?”
Foreign tourists are often confused in Japan because most streets there don’t have names. In Japan, people use landmarks(地标) in their directions instead of street names. For example, the Japanese will say to travelers, “Go straight down to the corner. Turn left at the big hotel and go past a fruit market. The post office is across from the bus stop.”
In the countryside of the American Midwest, there are not usually many landmarks. There are no mountains, so the land is very flat; in many places there are no towns or buildings within miles. Instead of landmarks, people will tell you directions and distances. In Kansas or Iowa, for example, people will say, “Go north two miles. Turn east, and then go another mile.”
People in Los Angeles, California, have no idea of distance on the map. They measure distance in time, not miles. “How far away is the post office?” you ask. “Oh,” they answer, “it’s about five minutes from here.” You say, “Yes, but how many miles away is it?” They don’t know.
It’s true that a person doesn’t know the answer to your question sometimes. What happens in such a situation? A New Yorker might say, “Sorry, I have no idea.” But in Yucatan, Mexico, no one answers “I don’t know.” People in Yucatan believe that “I don’t know” is impolite. They usually give an answer, often a wrong one. A tourist can easily get lost in Yucatan! (268 words)
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A. describe the place carefully B. show him a map of the place
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People in Yucatan may give a tourist a wrong answer ______.
A. in order to save time B. to show the right way
C. so as to be polite D. for fun
What can we infer from the text?
A. It’s important for travelers to understand cultural differences.
B. It’s useful for travelers to know how to ask the way properly.
C. People have similar understandings of politeness.
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Some plants have their own ways to keep animals away. For example, the leaves of the holly plant have sharp spines (刺) that discourage grass-eating animals. Holly leaves on lower branches have more spines than leaves on upper branches. This is because the lower leaves are easier for most animals to reach.
Some plants, such as the oak tree, have thick and hard leaves that are difficult for animals to eat. Some grasses may contain a sandy material; eating such grasses wears down the animal's teeth.
Many plants also have chemical defenses. Some plants produce chemicals that taste bitter or cause an unpleasant reaction. Some plants may fight against an attack by increasing the production of these chemicals. When a caterpillar (毛虫) bites a tobacco leaf, the leaf produces a chemical messenger. This messenger sends to the roots the information to produce more nicotine. The higher levels of nicotine discourage the caterpillar.
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