职称英语理工A阅读理解必考文章字典版

第九篇An Essential Scientific Process一个至关重要的科学过程

All life on the earth depends upon green plants. Using sunlight, the plants produce their own food. Then animals feed upon the plants. They take in the nutrients the plants have made and stored. But that’s not all. Sunlight also helps a plant produce oxygen. Some of the oxygen is used by the plant, but a plant usually produces more oxygen than it uses. The excess oxygen is necessary for animals and other organisms

to live.

The process of changing light into food and oxygen is called photosynthesis. Besides light energy from the sun, plants also use water and carbon dioxide. The water gets to the plant through its roots. The carbon dioxide enters the leaves through tiny openings called stomata. The carbon dioxide travels to chloroplasts, special cells in the bodies of green plants. This is where photosynthesis takes place. Chloroplasts contain the chlorophylls that give plants their green color. The chlorophylls are the molecules that trap light energy. The trapped light energy changes water and carbon dioxide to produce oxygen and a simple sugar called glucose.

Carbon dioxide and oxygen move into and out of the stomata. Water vapor also moves out of the stomata. More than 90 percent of water a plant takes in through its roots escapes through the stomata. During the daytime, the stomata of most plants are open. This allows carbon dioxide to enter the leaves for photosynthesis. As night falls, carbon dioxide is not needed. The stomata of most plants close. Water loss stops.

If photosynthesis ceased, there would be little food or other organic matter on the earth. Most organisms would disappear. The earth’s atmosphere would no longer contain oxygen. Photosynthesis is essential for life on our planet.

练习：

1．In the first paragraph，the word “excess”means. B extra.

2．Which of the following does not move through a plant’s stomata? D Food. 3．In the title, the term Essential Scientific Process refers to

A photosynthesis.

4．This passage is primarily developed by A explaining a process.

5．Another good title for this passage would be C How Photosynthesis Works.

第二十二篇Real World Robots现实世界中的机器人

When you think of a robot, do you envision a shiny, metallic device having the same general shape as a human being, performing humanlike functions, and responding to your questions in a monotone voice accentuated by high-pitched tones and beeps? This is the way many of us imagine a robot, but in the real world, a robot is not humanoid at all. Instead a robot often is a voiceless, box-shaped machine that efficiently carries out repetitive or dangerous functions usually performed by humans. Today’s robot is more than an automatic machine that performs one task again and again. A modern robot is programmed with varying degrees of artificial intelligence —that is, arobot contains a computer program that tells it how to perform tasks associated with human intelligence, such as reasoning, drawing conclusions, and learning from past experience.

A robot does not possess a human shape for the simple reason that a two-legged robot has great difficulty remaining balanced. A robot does, however, move from place to place on wheels and axles that roll and rotate. A robot even has limbs that swivel and move in combination with joints and motors. To find its way in its surroundings, a robot utilizes various built-in sensors. Antennae attached to the robot’s base detect anything they bump into. If the robot starts to teeter as it moves on anincline, a gyroscope or a pendulum inside it senses the vertical differential.To determine its distance from an object and how quickly it will reach theobject，the robot bounces beams of laser light and ultrasonic sound waves off obstructions in its path. These and other sensors constantly feed information to the computer, which then analyzes the information and corrects or adjusts the robot’s actions. As science and technology advance, the robot too will progress in its functions and use of artificial-intelligence programs.

练习：

1．Another good title for this passage would be .

C Today’s Robots and How They Function.

2．Artificial intelligence is .

D a computer program that imitates human intellectual processes.

3．The last paragraph suggests that future robots will be .

A more humanlike in behavior and actions.

4．The writer begins the passage by comparing .

B a modem robot with a fictional robot.

5．The word humanoid means .

D having a human form or characteristics.

第三十四篇Batteries Built by Viruses病毒电池

What do chicken pox，the common cold, the flu，and AIDS have in common? They’re all disease caused by viruses, tiny microorganisms that can pass from person to person．It's no wonder that when most people think about viruses, finding ways t0 steer clear of viruses is what's on people's minds．

Not everyone runs from the tiny disease carders, though．In Cambridge, Massachusetts, scientists have discovered that some viruses can be helpful in an unusual way．They are putting viruses to work, teaching them to build some of the world's smallest rechargeable batteries．

Viruses and batteries may seem like an unusual pair，but they're not so strange for engineer Angela Belcher，who first came up with the idea．At the Massachusetts Institute of Technology (MIT) in Cambridge, she and her collaborators bring together different areas of science in new ways．In the case of the virus-built batteries, the scientists combine what they know about biology, technology and production techniques．

Belcher's team includes Paula Hammond，who helps put together the tiny batteries, and Yet-Ming Chiang，an expert on how to store energy in the form of a battery．“We’re working on things we traditionally don’t associate with nature．”says Hammond．

Many batteries are already pretty small．You can hold A, C and D batteries in your hand．The coin—like batteries that power watches are often smaller than a penny．However。every year，new electronic devices like personal music players or cell phones get smaller than the year before．As these devices shrink, ordinary batteries won't be small enough to fit inside．

The ideal battery will store a lot of energy in a small package．Right now, Belcher's model battery, a metallic disk completely built by viruses, looks like a regular watch battery．But inside，its components are very small—so tiny you can only see them with a powerful microscope．

How small are these battery parts? To get some idea of the size，pluck one hair from your head．Place your hair on a piece of white paper and try to see how wide your hair is—pretty thin，right? Although the width of each person's hair is a bit different，you could probably fit about l o of these virus—built battery parts，side to side，across one hair．These microbatteries may change the way we look at viruses．

练习：

1．According to the first paragraph, people try to

C．stay away from viruses because they are causes of various diseases.

2．What is Belcher's team doing at present?

C．It is making batteries with viruses.

3．What expression below is opposite in meaning to the word "shrink" appearing in paragraph 5？

D．Expand.

4. Which of the following is true of Belcher's battery mentioned in paragraph 6？

D．It is a metallic disk with viruses inside it.

5. How tiny is one battery part?

A．Its width is one tenth of a hair.

第三十五篇Putting Plants to Work植物效能

Using the power of the sun is nothing new. People have had solar-powered calculators and buildings with solar panels for decades. But plants are the real experts: They’ve been using sunlight as an energy source fo r billions of years.

Ceils in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide, and water into1 sugars and starches, stored energy that the plants can use. This conversion process is called photosynthesis. Unfo rtunately, unless you’re a plant, it’s difficult and expensive to convert sunlight into storable energy. That’s why scientists are taking a closer look at exactly how plants do it.

Some scientists are trying to get plants, or biological cells that act like plants, to work as miniature photosynthetic power stations. For example, Mafia Ghirardi of the National Renewable Energy Laboratory in Golden, Colo.2, is working with green algae3. She’s trying to trick them into producing hydrogen4 instead of suga rs when they perform photosynthesis. Once the researchers can get the algae working efficiently, the hydrogen that they produce could be used to power fuel cells in cars or to generate electricity.

The algae are grown in narrow-necked glass bottles to produce hydrogen in the lab. During photosynthesis, plants normally make sugars or starches. “But under certain conditions, a lot of algae are able to use the sunlight energy not to store starch, but to make hydrogen,” Ghirardi says. For example, algae will produce hydrogen in an air free environment. It’s the oxygen in the air that prevents algae from making hydrogen most of the time.

Working in an air free environment, however, is difficult. It’s not a practical way to produce cheap energy. But Ghirardi and her colleagues have discovered that by removing a chemical called sulfate from the environment that the algae grow in, they will make hydrogen instead of sugars, even when air is present.

Unfortunately, removing the sulfate also makes t he algae’s cells work very slowly, and not much hydrogen is produced. Still, the researchers see this as a first step in their goal to produce hydrogen efficiently from algae. With more work, they may be able to speed the cells' activity and produce larger quantities of hydrogen.

The researchers hope that algae will one day be an easy-to-use fuel source. The organisms are cheap to get and to feed, Ghirardi says, and they can grow almost anywhere: “You can grow them in a reactor, in a pond. You can gr ow them in the ocean. There’s a lot of flexibility in how you can use these organisms.”

练习：

1. What does the writer say about plants concerning solar energy?

C）Plants have been using solar energy for billions of years.

2. Why do some scientists study how plants convert sunlight carbon dioxide, and water into sugars and starches?

B）Because they want green plants to become a new source of energy.

3. According to the fifth paragraph, under what conditions are algae able to use solar energy to make hydrogen?

B）When there is no oxygen in the air.

4. Researchers have met with difficulties when trying to make algae produce hydrogen efficiently. Which one of the following is one such difficulty?

D）It is too slow for algae to produce hydrogen when the sulfate is removed.

5. What is NOT true of algae?

C）They are cheap to eat.

第三十六篇Listening Device Provides Landslide Early Warning听觉仪器提供早期山崩预警

A device that provides early warning of a landslide by monitoring vibrations in soil is being tested by UK researchers. The device could save thousands of lives each year by warning when an area should be evacuated, the scientists say. Such natural disasters are common in countries that experience sudden, heavy rainfall, and can also be triggered by earthquakes and even water erosion.

Landslides start when a new particles of soil or rock within a slope start to move, but the early stages can be hard to spot. Following this initial movement, “slopes can become unstable in a matter of hours or minutes,” says Ne ll Dixon at Loughborough University1, UK. He says a warning system that monitors this movement “might be enough to evacuate a block of flats or clear a road, and save lives.”

The most common way to monitor a slope for signs of an imminent landslide is to watch for changes in its shape. Surveyors can do this by measuring a site directly, or sensors sunk into boreholes or fixed above ground can be used to monitor the shape of a slope. Slopes can, however, change shape without triggering a landslide, so either method is prone to causing false alarms. Now Dixon’s team has developed a device that listens for the vibrations caused when particles begin moving within a slope.

The device takes the form of a steel pipe dropped into a borehole in a slope. The borehole is filled in with gravel around the pipe to help transmit high-frequency vibrations generated by particles within the slope. These vibrations pass up the tube and are picked up by a sensor on the surface. Software analyses the vibration signal to determine whether a landslide may be imminent.

The device is currently being tested in a 6-metre-tall artificial clay embankment in Newcastle2, UK. Early results suggest it should provide fewer false positives than existing systems. Once it has been carefully and thoroughly tested, the device could be used to create a complete early-warning system for dangerous slopes.

“Locations with a significant risk of landslides could definitely benefit from a machine like this,” says Adam Poulter, an expert at the British Red Cross. “As long as it doesn’t cost too much.” But, Poulter adds that an early-warning system may not be enough on its own. “You need to have the human communication,” he says. “Making systems that get warnings to those who need them c an be difficult.”

练习:

1. What does “Such natural disasters” in the first paragraph refer to?

D Landslides.

2. Which of the following statements is true of landslides?

D All of the above.

3. Why do researchers develop a new device to monitor signs of landsides?

C Because the common methods can cause false alarms.

4. Which of the following statements is NOT true of the device, according to Paragraph 4?

A It is filled in with gravel.

5. According to the context, what does the word “positives” in the f ifth paragraph mean?

B Evidences.

第三十七篇“Don’t Drink Alone”Gets New Meaning不要在就餐时间以外饮酒有了新含义

In what may be bad news for bars and pubs, an European research group has found that people drinking alcohol out side of meals have a significantly higher risk of cancer in the mouth and neck than do those taking their libations with food.1 Luigino Dal Maso and his colleagues studied the drinking patterns of 1,500 patients from four cancer studies2 and another 3,500 adults who had never had cancer.

After the researchers accounted for the amount of alcohol consumed, they found that individuals who downed a significant share of their alcohol outside of meals3 faced at least a 50 to 80 percent risk of cancer in the oral cavity, pharynx, and esophagus, when compared with people who drank only at meals. Consuming alcohol without food also increased by at least 20 percent the likelihood of laryngeal4 cancer. “Roughly 95 percent of cancers at these four sites5 traced to smoking or drinking6 by the study voluntee rs,” Dal Maso says. The discouraging news, his team reports, is that drinking with meals didn’t eliminate cancer risk at any of the sites.

For their new analyst, the European scientists divided people in the study into four groups, based on how many drinks they reported having in an average week7. The lowest-intake group included people who averaged up to8 20 drinks a week. The highest group reported downing at least 56 servings of alcohol weekly for an average of eight or more per day.9 Cancer risks for the mouth and neck sites rose steadily with consumption even for people who reported drinking only with meals. For instance, compared with people in the lowest-consumption group, participants who. drank 21 to 34 alcohol servings a week at least doubled their cancer risk for all sites other than the larynx10. If people in these consumption groups took some of those drinks outside meals, those in the higher consumption group at least quadrupled their risk for oral cavity and esophageal cancers.

People in the highest-consumption group who drank only with meals had 10 times the risk of oral cancer, 7 times the risk of pharyngeal cancer, and 16 times the risk of esophageal cancer compared with those who averaged 20 or fewer drinks a week with meals. In contrast, laryngeal cancer risk in the high-intake, with-meals-only group11 was only triple that12 in the low-intake consumers who drank with meals. “Alcohol can inflame tissues. Over time, that inflammation can trigger cancer.” Dal Maso says. He suspects that food reduced cancer risk either by partially coating digestive-tract tissues or by scrubbing alcohol of those tissues. He speculates that the reason laryngeal risks were dramatically lower for all study participants traces to the tissue’s lower exp osure to alcohol.

练习:

1. Researchers have found that the risk of cancer in the mouth and neck is higher with people

A who drink alcohol outside of meals.

2. Which of the following is NOT the conclusion made by the researchers about “drinking with meals”?

C It increases by 20 percent the possibility of cancer in all sites.

3. Approximately how many drinks do the lowest-intake group average per day?

A 3 drinks.

4. Which cancer risk is the lowest among all the four kinds of cancer mentioned in the passage?

B Laryngeal cancer.

5. According to the last paragraph, tissue’s lower exposure to alcohol

D reduces the risk of laryngeal cancer.

第三十八篇"Life Form Found" on Saturn's Titan土卫六上发现了生命迹象Scientists say they have discovered hints of alien life on the Saturn's moon. The discovery of a sort of life was announced after researchers at the US space agency, NASA, analyzed data from spacecraft Cassini, which pointed to the existence of methane-based form of life on Saturn's biggest moon.

Scientists have reportedly discovered clues showing primitive alien beings are "breathing" in Titan's dense atmosphere filled with hydrogen.

They argue that hydrogen gets absorbed before hitting Titan's planet-like surface covered with methane lakes and rivers. This, they say, points to the existence of some "bugs" consuming the hydrogen at the surface of the moon less than half the size of the Earth.

"We suggested hydrogen consumption because it's the obvious gas for life to consume on Titan, similar to the way we consume oxygen on Earth," says NASA scientist Chris McKay. "If these signs do turn out to be a sign of life, it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth."

To date, scientists have not yet detected this form of life anywhere, though there are liquid-water-based microorganisms on Earth that grow well on methane or produce it as a waste product. On Titan, where temperatures are around 90 Kelvin (minus 290 degrees Farenheit), a methane-based organism would have to use a substance that is liquid as its medium for living processes, but not water itself. Water is frozen solid on Titan's surface and much too cold to support life as we know it.

Scientists had expected the Sun's interactions with chemicals in the atmosphere to produce a coating of acetylene on Titan's surface. But Cassini detected no acetylene on the surface.

The absence of detectable acetylene on the Titan's surface can very well have a non-biological explanation, said Mark Allen, a principal investigator of the NASA Titan team.

"Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed," Allen said. "We have a lot of work to do to rule out possible non-biological explanations. It is more likely that a chemical process, without biology, can explain these results."

练习：

1 .What have scientists found about Saturn?

C They have found methane-based life on Titan.

2. What do scientists say about Titan?

A There are life clues there.

3. To date, scientists have not yet detected this form of life…(paragraph 5) What does "this form of life" refer to?

B Methane-based life.

4. What can be inferred from what Allen said?

A Scientists have different arguments over whether there is life on Titan.

5. Which of the following can replace the title of this passage?

D A different Life Form, a Possibility.

第三十九篇Clone Farm克隆农场

Factory farming could soon enter a new era of mass production. Companies in the US ar e developing the technology needed to “clone” chickens on a massive scale1. Once a chicken with desirable traits has been bred or genetically engineered2, tens of thousands of eggs, which will hatch into identical copies3, could roll off the production lines every hour. Billions of clones could be produced each year to supply chicken farms with birds that all grow at the same rate, have the same amount of meat and taste the same.

This, at least, is the vision of the US’s National Institute of Science and Technology, which has given Origen Therapeutics of Burlingame, California, and Embrex of North Carolina $4.7 million to help fund research4. The prospect has alarmed animal welfare groups, who fear it could increase the suffering of farm birds.

That’s unlikely to put off5 the poultry industry, however , which wants disease-resistant birds that grow faster on less food. “Producers would like the same meat quantity but to use reduced inputs to get there,” says Mike Fitzgerald of Origen. To meet th is demand, Origen aims to “create an animal that is effectively a clone”, he says. Normal cloning doesn’t work in birds because eggs can’t be removed and implanted. Instead, the company is trying to bulk-grow6 embryonic stem cells7 taken from fertilized eg gs as soon as they’re laid. “The trick is to culture8 the cells without them starting to distinguish, so they remain pluripotent,” says Fitzgerald.

Using a long-established technique, these donor cells will then be injected into the embryo of a freshly laid, fertilized recipient egg9, forming a chick that is a “chimera”. Strictly speaking a chimera isn’t a clone, because it contains cells from both donor and recipient. But Fitzgerald says it will be enough if, say, 95 percent of a chicken’s body develops from donor cells. “In the poultry world, it doesn’t matter if it’s not 100 percent,” he says.

Another challenge for Origen is to scale up10 production. To do this, it has teamed up with11 Embrex, which produces machines that can inject vaccines into up to 50,000 eggs12 an hour. Embrex is now trying to modify the machines to locate the embryo and inject the cells into precisely the right spot without killing it.

In future, Origen imagines freezing stem cells from different strains of chicken13. If orders come in for a particular strain, millions of eggs could be produced in months or even weeks. At present, maintaining all the varieties the market might call for is too expensive for breeders, and it takes years to bread enough chickens to produce the billions of eggs that farmers need.

练习:

1. Which statement is the best description of the new era of factory farming according to the first paragraph?

C Cloned chickens are hulk-produced with the same growth rate, weight, and taste. 2. Which institution has offered $ 4.7 million to fund the research?

A The US’s National Institute of Science and Technology.

3. In the third paragraph, by saying “Producers would like the same meat quantity but to use reduced inputs to get there,” Mike Fitzgerald means that he wishes

D chickens could grow to the same weight but with less feed.

4. Which of the following statements about Origen and Embrex is correct according to the fifth paragraph?

C Origen has joined hands with Embrex in producing cell-injecting machines.

5. The technology of freezing stem cells from different strains of chicken can do all the following EXCEPT that

A farmers can order certain strains of chicken only.

第四十篇Teaching Math, Teaching Anxiety教数学，教焦虑

In a new study about the way kids learn math in elementary school, the psychologists at the University of Chicagol Sian Beilock and Susan Levine found a surprising relationship between what female teachers think and what female students learn: If a female teacher is uncomfortable with her own math skills, then her female students are more likely to believe that boys are better than girls at math.

"If these girls keep getting math-anxious female teachers in later grades, it may create a snowball effect on their math achievement said Levine. In other words, girls may end up learning math anxiety from their teachers. The study suggests that if these girls grow up believing that boys are better at math than girls are, then these girls may not do as well as they would have if they were more confident.

Just as students find certain subjects to be difficult, teachers can find certain subjects to be difficult to learn — and teach. The subject of math can be particularly difficult for everyone. Researchers use the word "anxiety" to describe such feelings: anxiety is uneasiness or worry.

The new study found that when a teacher has anxiety about math, that feeling can influence how her female students feel about math. The study involved 65 girls, 52 boys and 17 first-and second-grade teachers in elementary schools in the Midwest. The students took math achievement tests at the beginning and end of the school year, and the researchers compared the scores.

The researchers also gave the students tests to tell whether the students believed that a math superstar had to be a boy. Then the researchers turned to the teachers: To find out which teachers were anxious about math, the researchers asked the teachers how they felt at times when they came across math, such as when reading a sales receipt. A teacher who got nervous looking at the numbers on a sales receipt, for example, was probably anxious about math.

Boys, on average, were unaffected by a teacher's anxiety. On average, girls with math-anxious teachers scored lower on the end-of-the-year math tests than other girls in the study did. Plus, on the test showing whether someone thought a math superstar had to be a boy, 20 girls showed feeling that boys would be better at math — and all of these girls had been taught by female teachers who had math anxiety.

"This is an interesting study, but the results need to be interpreted as preliminary and in need of replication with a larger sample," said David Geary, a psychologist at the University of Missouri in Columbia.

练习：

1. What is the result of the research at the University of Chicago, according to the first paragraph?

D Female teachers' confidence in their math skills is related to girl's math skills.

2. What is implied in the third paragraph?

B A difficult subject like math may affect teachers' confidence in teaching the subject.

3. According to the experiment, those teachers were probably anxious about math when they felt

C uneasy reading the numbers of a sales receipt.

4. The sixth paragraph tells us that the research findings

A prove a strong link between female teachers' math anxiety and their female students' math achievements.

5. David Geary thinks that

B the research results need to be retested based on a larger sample.

第四十一篇Too Little for Global Warming 全球变暖“缺油”

Oil and gas will run out1 too fast for doomsday global warming scenarios2 to materialize, according to a controversial new analysis presented this week at the University of Uppsala in Sweden. The authors warn that all the fuel will be burnt before there is enough carbon dioxide in the atmosphere to realize predictions of melting ice caps and searing temperatures. Defending their predictions, scientists from the Intergovernmental Panel on Climate Change3 say they considered a range of estimates of oil and gas reserves, and point out that coal-burning could easily make

up4 the shortfall. But all agree that burning coal would be even worse for the planet.

The IPCC’s predictions of global meltdown pushed forward5 the 1997 Kyoto Protocol6, an agreement obliging signatory nations to cut CO2 emissions. The IPCC considered a range of future scenarios, from unlimited burning of fossil-fuels to a fast transition towards greener energy sources. But geologists Anders Sivertsson, Kjell Aleklett and Colin Campbell of Uppsala University say there is not enough oil and gas left even the most conservative of the 40 IPCC scenarios to come to pass7.

Although estimates of oil and gas reserves vary widely, the researchers are part of a growing group of experts who believe that oil supplies will peak as soon as 2010, and gas soon after. Their analysis suggests that oil and gas reserves combined amount to the equivalent of about 3,500 billion barrels of oil considerably less than the 5,000 billion barrels estimated in the most optimistic model envisaged by the IPCC. Even the average forecast of about 8,000 billion barrels is more than twice the Swedish estimate of the world’s remaining reserves.

Nebojsa Nakicenovic, an energy economist at the University of Vienna, Austria who headed the 80-strong IPCC team that produced the forecasts, says the panel’s work still stands8. He says they factored in9 a much broader and internationally accepted range of oil and gas estimates than the “conservative” Swedes.

Even if oil and gas run out. “there’s a huge amount of coal underground that could be exploited.” He says that burning coal could make the IPCC scenarios come true, but points out that such a switch would be disastrous. Coal is dirtier than oil and gas and produces more CO2 for each unit of energy, as well as releasing large amounts of particulates. He says the latest analysis is a “shot across the bows10” for policy makers.

练习:

1. What do the authors of the new analysis presented at the University of Uppsala intend to say?

D Oil and gas w ill run out so fast that Earth’s doomsday will never materialize.

2. Nations that signed the Kyoto Protocol agree to

B cut CO2 emissions.

3. What are the estimates of the world’s oil and gas reserves?

D 3,500 billion by a growing number of scientists.

4. Which of the following about Nebojsa Nakicenovic is true?

D He thinks that IPCC’s estimates are more optimistic than the Swedes.

5. Which of the following is the near explanation of Nakicenovic's assertion that “… such a switch would be disastrous…”?

B A switch to burning coal would produce disastrous environmental problems.

第四十二篇Renewable Energy Sources可再生能源

Today petroleum provides around 40% of the world’s energy needs, mostly fuelling automobiles1. Coal is still used, mostly in power stations, to cover one-quarter of our energy needs, but it is the least efficient, unhealthiest and most environmentally damaging fossil fuel2. Natural gas reserves could plug some of the gap from oil3, but reserves of that will not last into the 22nd century either. Most experts predict we will exhaust easily accessible reserves within 50 years4. We could fast reach an energy crisis. We need to rapidly develop sustainable solutions to fuel our future5.

Less-polluting renewable energy sources offer a more practical long-term energy solution. They may benefit the world’s poor too. “Renewable”, refers to the fact that these resources are not used faster than they can be replaced.

The Chinese and Romans used watermills over 2,000 years ago. But the first hydroelectric dam was built in England in 1870. Hydroelectric power is now the most common form of renewable energy, supplying around 20% of world electricity. China’s Three Gorges Dam6, which has just been completed, is the largest ever. At five times the size of the US’s Hoover Dam7, its 26 turbines will generate the equivalent energy of 18 coal-fired power stations8. It will satisfy 3% of China’s entire electricity demand. Surprisingly, some argue that hydroelectric dams significantly contribute greenhouse gases.

In 2003, the first commercial power station to harness tidal currents9 in the open sea opened in Norway. It is designed like windmill, but others take the form of turbines.

As prices fall, wind power has become the fastest growing type of electricity generation — quadrupling10 worldwide between 1999 and 2005. Modern wind farms consist of turbines that generate electricity. Though it will be more expensive, there is more than enough wind to provide the world’s entire energy needs. Wind farms com e in onshore and offshore forms. They can often end up at spots of natural beauty11, and are often unpopular with residents. And turbines are not totally benign — they can interfere with radar and leave a significant ecological footprint12, altering climate and killing sea birds. Migrating birds may have more luck avoiding them. Scotland is building Europe’s largest wind farm, which will power 200,000 homes. The UK’s goal is to generate one-fifth of power from renewable sources, mainly wind, by 2020. But this may cause problems, because wind is unreliable.

练习:

1. What are the energy resources that are not renewable according to the article?

D A. Petroleum and coal and B. Natural gas

2. China’s Three Gorges Dam

C is the largest of all the hydroelectric dams in the world.

3. Which is the country with the first commercial power station that makes use of ocean currents produced by tides?

B Norway.

4. Which of the following statements is true of wind power?

D All of the above.

5. According to the article, resources such as wind

B are renewable so sustainable.

第四十三篇Forecasting Methods天气预报的方法

There are several different methods that can be used to create a forecast. The method a forecaster chooses depends upon the experience of the forecaster, the amount of information available to the forecaster, the level of difficulty that the forecast situation presents, and the degree of accuracy or confidence1 needed in the forecast.

The first of these methods is the persistence method; the simplest way of producing a forecast. The persistence method assumes that the conditions at the time of the forecast will not change. For example, if it is sunny and 87 degrees today, the persistence method predicts that it will be sunny and 87 degrees tomorrow. If two inches of rain fell today, the persistence method would predict two inches of rain for tomorrow. However, if weather conditions change significantly2 from day to day, the persistence method usually breaks down3 and is not the best forecasting method to use.

The trends method involves determining4 the speed and direction of movement for fronts5, high and low pressure centers, and areas of clouds and precipitation. Using this information, the forecaster can predict where he or she expects those features6 to be at some future time. For example, if a storm system is 1,000 miles west of your location and moving to the east at 250 miles per day, using the trends method you would predict it to arrive in your area in 4 days. The trends method works well when systems7 continue to move at the same speed in the same direction for a long period of time. If they slow down, speed up, change intensity, or change direction8, the trends forecast will probably not work as well.

The climatology method is another simple way of producing a forecast. This method involves averaging weather statistics accumulated over many years to make the forecast. For example, if you were using the climatology method to predict the weather for New York City on July 4th, you would go through all the weather data that has been recorded for every July 4th and take an average. The climatology method only works well when the weather pattern is similar to that expected for the chosen time of year. If the pattern is quite unusual for the given time of year, the climatology method will often fail.

The analog method is a slightly more complicated method of producing a forecast. It involves examining today’s forecast scenario and remembering a day in the past when the weather scenario looked very similar (an analog9). The forecaster would predict that the weather in this forecast will behave the same as it did in the past. The analog method is difficult to use because it is virtually10 impossible to find a predict analog. Various weather features rarely align themselves in the same locations as they were in the previous time11. Even small differences between the current time and the analog can lead to very different results.

练习:

1. What factor is NOT mentioned in choosing a forecasting method?

A Imagination of the forecaster.

2. Persistence method will work well

B if weather conditions do not change much.

3. The limitation of the trends method is the same as the persistence method in that

D the weather features need to be constant for a long period of time.

4. Which method may involve historical weather data?

C Both climatology method and analog method.

5. It will be impossible to make weather forecast using the analog method

A when the current weather scenario differs from the analog.

第四十四篇Defending the Theory of Evolution1 Still Seems Needed捍卫进化论仍必要

Judith S. Weis, a biology professor who serves as2 president of the American Institute of Biological Sciences (AIBS) is leading a nationwide effort to “defend” the theory of evolution. Weis leads the effort in the face of what the institute views as opposition and indifference from school boards and government entities3.

The Institute believes that the teaching of evolution in America is being diminished by the teaching of creationism as well as by an overall lack of teaching Darwin’s4 theory in high school. “There’s nothing that requires schools to teach evolution. Sometimes teachers in high schools just leave it out5. However, from the point of view of biologists, evolution is the central theory of biology upon which everything is based,” said Weis. “Unfortunately, teaching evolution has become a political issue in many parts of the country and AIBS, as a representative of biologists, wanted to be a major force speaking o ut in favor of its teaching6.”

Weis said the institute is working together with the American Geological Institute and the National Association of Biology Teachers and its 80-plus member organizations7 to address8 the political and legislative threats to teaching evolution. In states challenging its teaching, the institute responds by sending letters to school boards and state legislatures, by providing testimony at public meetings and by notifying members and affiliated organizations. AIBS, with more than 80 member societies and 250,000 members, has established an e-mail system enabling scientists and teachers in each state, and member societies, to keep each other informed about threats to the teaching of evolution.

Darwin’s theory of evolutio n holds that living things change and adapt to their environment and that present-day species (including human beings) are descended from earlier species through modification by natural selection. The theory has been accepted by scientists for nearly 100 years, Weis said, and has been refined, extended and strengthened over the years by findings in paleontology and developmental biology.

Discoveries in genetics, molecular biology9 and genomics — all of which provide significant benefits for human health — would not be possible without the underlying10 knowledge of evolution. And, Weis adds, “modern molecular biology and genomics have increased our understanding of how evolution works.” Nonetheless, evolution remains a politically. if not scientifically, controversial issue.

Weis said that this year alone, seven states have had either local or statewide efforts to water down11 the teaching of evolution, or “balance” it with the teaching of creationism — a religious belief that different species were created separately by a higher power, such as God. “Rarely does anyone now use the word ‘creationism,’ because that’s too obvious,” Weis said. “The current terminology is ‘intelligent design’.”

练习:

1. According to the first paragraph, which of the following statements about the theory of evolution is true?

B School boards oppose AIBS’s effort to defend the theory of evolution.

2. Which one of the following is NOT the reason for an overall lack of teaching Darwin’s theory?

D Darwin’s theory is denied as th e central theory of biology.

3. AIBS is composed of

A more than 80 societies and 250,000 members.

4. According to Weis in the 5th paragraph, the theory of evolution

A is fundamental to the development of modern genetics, molecular biology and genomics.

5. Why do people replace the term creationism with the term intelligent design nowadays？

D Because the term creationism is too direct.

第四十五篇Small But Wise小而聪明

On December 14, NASA blasted a small but mighty telescope into space. The telescope is called WISE and is about as wide around as a trashcan. Don't let its small size fool you: WISE has a powerful digital camera, and it will be taking pictures of some the wildest objects in the known universe, including asteroids, faint stars, blazing galaxies and giant clouds of dust where planets and stars are born.

“I'm very excited because we're going to be seeing parts of the universe that we haven't seen before, ”said Ned Wright, a scientist who directs the WISE project.

Since arriving in space, the WISE telescope has been circling the Earth, held by gravity in a polar orbit (this means it crosses close to the north and south poles with each lap). Its camera is pointed outward, away from the Earth, and WISE will snap a picture of a different part of the sky every 11 minutes. After six months it will have taken pictures across the entire sky.

The pictures taken by WISE won't be like everyday digital photographs, however. WISE stands for “Wide-field Infrared Survey Explorer.”As its name suggests, the WISE camera takes pictures of features that give off infrared radiation.

Radiation is energy that travels as a wave. Visible light, including the familiar spectrum of light that becomes visible in a rainbow, is an example of radiation. When an ordinary digital camera takes a picture of a tree, for example, it receives the waves of visible light that are reflected off the tree. When these waves enter the camera through the lens, they're processed by the camera, which then puts the image together.

Waves of infrared radiation are longer than waves of visible light, so ordinary digital cameras don't see them, and neither do the eyes of human beings. Although invisible to the eye, longer infrared radiation can be detected as warmth by the skin.

That's a key idea to why WISE will be able to see things other telescopes can't. Not everything in the universe shows up in visible light. Asteroids, for example, are giant rocks that float through space —but they absorb most of the light that reaches them. They don't reflect light, so they're difficult to see. But they do give off infrared radiation, so an infrared telescope like WISE will be able to produce images of them. During its mission WISE will take pictures of hundreds of thousands of asteroids. Brown dwarfs are another kind of deep-space object that will show up in WISE's pictures. These objects are “failed” stars — which means they are not massive enough to jump start the same kind of reactions that power stars such as the sun. Instead, brown dwarfs simply shrink and cool down. They're so dim that they're almost impossible to see with visible light, but in the infrared spectrum they glow.

练习：

1. What is so special about WISE?

C Its digital camera can help astronomers to see the unknown space.

2. Which is NOT the synonym for the word "snap" in the third paragraph?

A make.

3. The camera on WISE

C catches the infrared radiation while the ordinary camera does not.

4. Which of the following is NOT correct about "asteroids" according to paragraph 7?

A Asteroids float through space giving off visible light.

5.What is implied in the last paragraph?

B Brown dwarfs give off infrared radiation.

第四十六篇Ants Have Big Impact on Environment as "Ecosystem Engineers"蚂蚁作为“生态系统工程师”对环境影响巨大

Research by the University of Exeter1 has revealed that ants have a big impact on their local environment as a result of their activity as "ecosystem engineers" and predators. The study, published in the Journal of Animal Ecology, found that ants have two distinct effects on their local environment.

Firstly, through moving of soil by nest building2 activity and by collecting food they affect the level of nutrients in the soil. This can indirectly impact the local populations of many animal groups, from decomposers to species much higher up the food chain.

Secondly, they prey on a wide range of other animals, including larger prey which can be attacked by vast numbers of ant workers.

Dirk Sanders, an author of the study from the university's Centre for Ecology and Conservation, said: "Ants are very effective predators which thrive in huge numbers. They're also very territorial3 and very aggressive, defending their resources and territory against other predators. All of this means they have a strong influence on their surrounding area."

"In this research, we studied for the first time how big this impact is and the subtleties of it. What we found is that despite being predators, their presence can also lead to an increase in density and diversity of other animal groups4. They genuinely play a key role in the local environment, having a big influence on the grassland food web," Sanders said.

The study, carried out in Germany, studied the impact of the presence of different combinations and densities of black garden ants and common red ants, both species which can be found across Europe, including in the UK. It found that a low density of ants in an area increased the diversity and density of other animals in the local area, particularly the density of herbivores and decomposers. At higher densities ants had no or the opposite effect, showing that predation is counteracting the positive influence.

Dr Frank van Veen, another author on the study, said: "What we find is that the impact of ants on soil nutrient levels has a positive effect on animal groups at low levels, but as the number of ants increases, their predatory impacts have the bigger effect — thereby counteracting the positive influence via ecosystem engineering." Ants are important components of ecosystems not only because they constitute a great part of the animal biomass5 but also because they act as ecosystem engineers. Ant biodiversity6 is incredibly high and these organisms are highly responsive to human impact, which obviously reduces its richness. However, it is not clear how such disturbance damages the maintenance of ant services to the ecosystem．Ants are important in below ground processes8 through the alteration of the physical and chemical environment and through their effects on plants, microorganisms, and other soil organisms.

练习：

1 .Why are ants compared to ecosystem engineers?

C Because their activity affects the environment.

2. As predators, ants

A prey on small as well as large animals.

3. Dir Sanders' study centered on how ants

D produce such a big impact on the environment.

4. What does paragraph 6 tell us?

B Ants bring about a positive influence to an area when their population is small.

5. What still remains unclear about ants, according to the last paragraph?

C How do human activities affect ants' influence on a given ecosystem?

第四十七篇Listening to Birdsong倾听鸟鸣

A male zebra finch1 chirps away2to himself. Suddenly he notices a female bird nearby. He realizes he has an audience and immediately changes his song. Can the female tell the difference in his performance? According to a new study, the female zebra finch knows. And she prefers the special trills he creates when he sings to her. A male zebra finch changes his song when singing to a female in ways that people can barely detect. But the female finch can tell the difference.

Scientists had noticed slight variations in the songs of male zebra finches based on whether they were singing alone or whether there was a female（and potential mate）nearby. With an audience, the males sped up the pace of their songs and controlled the notes they used.

For this study, researchers Sarah C. Woolley and Allison Doupe at the University of California, San Francisco decided to focus attention on the listening females, which have not been well studied in the past.

In the study, Woolley and Doupe set up a long cage with a sound speaker at each end. One broadcast the sound of a male zebra finch singing to himself, like someone singing in the shower. The other speaker broadcast a male performing for a female audience, as if he was giving a concert.

Female birds were placed between the two speakers. Some of the birds had mates, others didn’t. The females shifted around a bit, and then most of them hopped over to sit beside just one speaker. All the birds that made a clear choice liked songs meant for a female audience, even if they’d never met the male.

Mated females also had a chance to listen to two different performance songs, one from an unknown male, and one from their mate. They spent more time listening

to the concert version of their mates’ songs. This suggests that after a while, females learn to recognize and prefer—the songs of their mates.

Scientists then studied the brains of the females. They found certain areas of the brain perked up3 when the birds listened to the concert songs. These brain areas may be involved in recognizing and evaluating the songs, and storing the memories of them.

This research deals with what’s called directed communication, when the communicator, or sender, focuses the message for a specific audience. One example is the way moms speak to their babies. Mothers around the world use the same sort of high-pitched4 sing-song chatter, and the babies respond best to those sounds. Songbirds are one of the only other species known to learn their communication, in

this case their songs.

练习：

1. What does the first paragraph say about zebra finches?

C）Male zebra finches change their songs in female zebra finches' presence.

2. What did the researchers find in their study of female zebra finches?

A）Female finches liked songs male finches sang for them.

3. What is meant by "concert songs" in the seventh paragraph?

B）Songs sung by male finches for female finches.

4. What is NOT true of directed communication? D）Male zebra finches sing to themselves.