In order to protect valuable energy, snails(蜗牛) basically play a game of follow-the-leader, a new study finds. Snails create trails of mucus(黏液) to help them move smoothly across the ground, mainly in search of food or a partner, but making all that mucus uses up a lot of energy.
“Snails use a lot of energy, probably a third, creating mucus,” said Mark Davies of the University of Sunderland, lead author of the study published in the journal Proceedings of the Royal Society. “This process is very tiring indeed— much more so than walking, swimming or flying.”
Davies and his workmates studied marine snails off the coast of Britain and discovered that to save some of this important energy, the snails sometimes follow the existing mucus trails laid down by other snails to get around and so only have to create a small part of the mucus needed to make a new trail.
“The fact that they can make savings has an effect on as much as they have to save more energy to do other things like reproducing,” Davies said.
The energy saving may also help snails which live in environments where food is not enough, making the energy harder to replace.
Biologists had long guessed that snails behaved this way, but this is the first study to directly observe it. Davies said that it is likely that all snails use this means of cutting energy as they work hard through life.
45. What’s the function of mucus that snails create?
A. To find their food B. To find their way back
C. To save their energy D. To help them move smoothly
46. According to the passage, which of the following statements is TRUE?
A. The snail’s life is very hard.
B. The snails don’t need much to reproduce.
C. This is the first time to do the guess.
D. The snails will replace more energy in places lacking food.
47. From the passage we know that ______.
A. snails’ trails are sometimes reused
B. snails’ food is difficult to find
C. snails can live a long life
D. only marine snails have the ability
48. What does the passage mainly talk about?
A. How snails move and work.
B. Snails save energy by reusing mucus trails.
C. A new study finds the mysteries of snails.
D. Snails make full use of their energy.
Tests administered（实施）to most elementary and high-school students in the United States exert（发挥）an unfavorable influence on science and math teaching， according to a new ＄1 million study performed for the National Science Foundation．And because schools with high minority enrollments（入学）generally place a greater reliance（相信）on scores from these tests， the study finds，there tends to be “a gap in instructional emphases between high and low minority classrooms that differs from our national concern for the quality of education．”
George F．Madaus and his colleagues at Boston College analyzed not only the six most widely used national standardized tests， but also the tests designed to accompany（go with）the four most commonly used science and math texts in fourth-grade，eighth-grade，and high-school classrooms．Though curriculum（teaching program）experts argue that schools should place greater emphasis on problem solving and reasoning， the new study shows that the tests focus on lower-level skills—primarily mechanical memorization of routine formulas（公式）．
Researchers surveyed more than 2，200 math and science instructors，interviewing in depth some 300 teachers and administrators．Especially in schools with high minority enrollments，teachers reported feeling pressured to help students perform well on these tests．Some states judge schools and some schools determine teacher assignments（工作安排）based on students' test scores．
“With so much worry，”Madaus says，“teachers feel forced to focus their instruction on drilling what the tests will measure—at the expense of the more valuable，higher-level skills．”
The author of this article states that ____ _ ．
| A．the tests don't affect teaching in most elementary and high schools |
| B．the science and math teaching is influenced by the present tests |
| C．no study is performed on tests for the National Science Foundation |
| D．the United States exerts a strong influence on science and math teaching |
It can be inferred that in high minority classrooms ____ _ ．
| A．the students can not get high score from the tests |
| B．scores from the tests are not important |
| C．instructional emphases are unfavourable |
| D．teaching doesn't focus on the quality of education |
According to the second paragraph，the study has discovered that ____ _ ．
| A．emphasis of teaching is on problem solving and reasoning |
| B．curriculum is good for national standardized tests |
| C．the tests mainly center around the memorization of some formulas |
| D．routine formulas are not useful for students to memorize |
According to Madaus' opinion，teachers are forced to ____ _ ．
| A．evaluate（评估）students' skills every year |
| B．suffer so much worry on the texts |
| C．teach what will be tested |
| D．focus their instruction on useful drillings |
Anti-bird flu contingency (意外事故) measures, including a proposal to separate poultry from humans and a series of traffic and logistics (后勤) measures will be discussed at the Legislative Council's Food Safety and Environmental Hygiene Panel meeting next month. Secretary for Health, Welfare and Food Dr York Chow says the contingency plan would come into force if an outbreak occurred near Hong Kong.
Speaking on a radio talk show this morning, Dr Chow said the separation of poultry from humans policy, which will be determined after a decision whether to set up a central slaughtering (屠宰) house or several regional ones, would be based on the demand for live chickens.
He pointed out that at present there were 30,000 live chickens imported from the Mainland and 30,000 supplied locally. If this demand persisted, there would be no central slaughtering house or wholesale point that could handle such an amount and regional slaughtering houses could be the choice.
He added that building of regional slaughtering houses took time, but stressed the need to study the views of the public and the sector before a final decision was made.
Regarding avian flu vaccination (种痘) for humans, Dr Chow said it was still being developed. He added that it may not be reliable in the case of an outbreak as records show vaccination can only offer 5% protection against a virus.
He said Hong Kong had more experience and expertise than neighbouring territories in the fight against viral outbreaks, and was willing to offer them help. He added there was no “boundary” for infectious diseases and close cooperation among different countries had to be maintained to fight against a possible outbreak.
It can be inferred from the first paragraph that ______.
| A．the government is planning to take strong action to fight against bird flu |
| B．an outbreak which happened near Hong Kong made people very frightened |
| C．anti-bird flu contingency measures will come into use next month |
| D．Dr York Chow will organize a meeting to discuss the contingency plan |
According to the passage, the best way to fight against bird flu is to ______.
| A．separate poultry from humans | B．set up a central slaughtering house |
| C．set up several regional slaughtering houses | D．get avian flu vaccination |
When the final decision will be made mainly depends on ______.
| A．the demand for live chickens | B．the views of the public |
| C．the advice from experts | |
| D．the time when regional slaughtering houses will be finished |
Which of the following statements isn’t Dr York Chow’s opinion?
| A．Hong Kong is better at dealing with viral outbreaks than its neighbours. |
| B．Infectious diseases could happen in any country. |
| C．Other territories should ask Hong Kong for help because it has more experience. |
| D．Cooperation is quite necessary when danger is coming. |
A black hole is created when a large star burns out. Like our sun, stars are unbelievably hot furnaces (熔炉) that burn their own matter as fuel. When most of the fuel is used up, the star begins to die.
The death of a star is not a quiet event. First there is a huge explosion. As its outer layer is blasted off into space, the dying star shines as brightly as a billion suns.
After the explosion gravity pulls in what’s left of the star. As the outside of the star sinks toward the center, the star gets smaller and smaller. The material the star is made of becomes tightly packed together. A star is so dense that a teaspoon of matter from it weighs billion of pounds.
The more the star shrinks, the stronger the gravity inside it becomes. Soon the star is very tiny, and the gravity pulling it in is unbelievably strong. In fact, the gravity is so strong that it even pulls light into the star! Since all the light is pulled in, none can go out. The star becomes black when there is no light. Then a black hole is born!
That’s what we know about black holes. What we don’t know is this: What happens inside a black hole after the star has been squeezed into a tiny ball? Does it keep getting smaller and smaller forever? Such a possibility is hard to imagine.
But if the black hole doesn’t keep shrinking, what happens to it? Some scientists think black holes are like doorways to another world. They say that as the star disappears from our universe, it goes into another universe. In other words a black hole in our universe could turn into a “white hole” in a different universe. As the black hole swallows light, the white hole shines brightly—somewhere else. But where? A different place, perhaps, or a different time — many years in the past or future.
Could you travel through a black hole? Right now, no. Nothing we know of could go into a black hole without being crushed. So far the time being, black hole must remain a mystery.
Black holes are a mystery—but that hasn’t stopped scientists from dreaming about them. One scientist suggested that in the future we might make use of the power of black holes. They would supply all of Earth’s energy needs, with plenty to spare. Another scientist wondered if a black hole could some day be used to swallow earthly waste—a sort of huge waste disposal(处理) in the sky!When the star begins to die ______.
| A．there is no fuel left in it | B．its outer layer goes into space first |
| C．a huge explosion will happen | D．it doesn’t give off light any longer |
Which of the following doesn’t help produce a black hole?
| A．The gravity inside the star is very strong. | B．The light can’t go out of the star. |
| C．The star becomes smaller and smaller | D．The dying star shines very brightly. |
The black hole ______.
| A．continues becoming smaller and smaller all the time |
| B．goes into another universe and becomes a white hole |
| C．can pull in everything we know of in the world |
| D．will appear at another place at a different time |
What’s the best title for this passage?
| A．A New Scientific Discovery: Black Holes |
| B．How Do Black Holes Come Into Being? |
| C．What Are Black Holes? |
| D．Travel Through A Black Hole |
BEIJING, Nov. 26—U.S. dollar hit another record low against the euro on Friday, with the European currency climbing above $1.32 for the first time. The green-back fell to its lowest in nearly five years against the yen the same day.
By 1943 EST, the dollar was trading at US$1.3265 per euro, compared with US$1.3270 in thin late New York trade. It was at 102.55 yen, little changed from New York after touching 102.37, a level not seen since March 2000, in London.
Japanese Finance Minister Sadakazu Tanigaki repeated his warning against dollar weakness, threatening to take action against sudden moves, but market participants said such verbal intervention (口头干涉) had long lost its clout.
Traders were expecting market liquidity to remain thin on Friday because of the extended U.S. holiday.
In such thin trading, many said a fall in the dollar past 102 yen and US$1.33 per euro was a real possibility.
Referring to recent currency movements as “brutal”, European Central Bank chief Jean-Claude Trichet, who is the most vocal European policymaker on dollar weakness, is due to make comments in Rio de Janeiro, along with ECB council member and Spanish central bank governor Jaime Caruana.
Introduced in 1999 as the common currency for 12 European countries, the euro initially(最初) dropped against the dollar but has risen some 60 percent since hitting an all-time low of 82 U.S. cents in October 2000.
What does “the green-back” refer to in the first paragraph?
| A．U.S. dollar | B．Another record |
| C．The euro | D．European currency |
How did Sadakazu Tanigaki feel about dollar weakness?
| A．Excited | B．Puzzled | C．worried | D．Disappointed |
The underlined word “brutal” probably means ______.
| A．cruelty | B．help | C．criticism | D．apology |
According to some people, it was possible for the dollar to trade ______.
| A．at 1.3265 per euro | B．at 1.32 per euro |
| C．at 1.3270 per euro | D．at 1.331 per euro |
| PRINT PRODUCTION MANAGER WANTED A well-known printing company, now well established in the UK and in the Far East, wishes to set up a manufacturing base in Europe. An experienced manager, responsible to the Production Director, is required to assist in setting up the department and will then take charge of the day-to-day work. The successful applicant will have had experience of modern methods and machines especially in the printing, multicolour work and finishing processes, he / she will have had at least three years’ experience in cost-effective management. A good working knowledge of English is essential. We offer excellent pay and prospects, with 4 week’s holiday a year plus public holidays, a company car, and a company pension scheme(养老金制度). Interviews will be arranged in the nearest city to applicant’s home. Write, with CV, to the Personnel Manager, Box 32507, Daily News, Kemsworth Street, Comston. United Kingdom SG186 37AH. |
| ASSISTANT PRINT PRODUCTION MANAGER An internationally recognized printing company is seeking to set up a manufacturing plant in Europe. We are appointing an assistant (male or female) to our Print Production Manager. The job-holder will carry out duties involving the buying of paper and of finishing equipment, will liaise (联络) with the supervisors of the various production lines, and will assist the Production Manager. At least three years’ experience on one or more lines as well as supervisory experience is needed. A working knowledge of English is required to communicate with colleagues in the UK. We offer excellent pay, prospects, holidays, pension scheme, sick pay, etc. Write to the Manager, Box 3526. Broad Street, Northby, Millshire BK 57PX. |
Both the printing companies ______.
| A．are well-known all over the world | B．require at least three years’ experience |
| C．offer excellent pay and sick pay | D．prefer to hire a man manager |
According to the first advertisement, the applicant living in a small village will ______.
| A．get in touch with the Personal Manager by telephone | |
| B．get the result on TV | C．be interviewed in a city |
| D．write to Box 3526 to get more information |
We can infer from the two advertisements that ______.
| A．the companies want to do business in Europe and Far East. |
| B．cars are necessary for the successful applicants. |
| C．the companies haven’t got telephones to save money. |
| D．applicants should write to the company first. |
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