游客
题文


Scientists are working to develop crop plants that can reduce the amount of water used for agriculture. Almost sixty percent of the world’s freshwater withdrawals from rivers, lakes and other water resources go toward irrigating fields.
Scientists are using biotechnology as well as traditional breeding methods to develop water-saving crops to feed a growing world.
Thomas “Tommy” Carter is a plant scientist in North Carolina. He works for the Agricultural Research Service in the United States Department of Agriculture. He leads Team Drought, a group of researchers at five universities. They have been using conventional breeding methods to develop and test soybeans that can grow well under dry conditions.
Tommy Carter started working on drought-resistant soybeans in 1981. His research has taken him as far as China, where soybeans have been grown for thousands of years.
Farmers in the United States, however, have grown soybeans for only about a century. Tommy Carter says the soybeans they grow are for the most part genetically similar. More differences could better protect crops against climate changes that can reduce production. Those changes include water shortages which could increase from global warming.
The Agriculture Department has a soybean germplasm(胚质) collection, a collection of genetic material passed from one generation to the next. Members of Team Drought studied more than 2,500 examples from the collection.
They looked at ones from the home of soybeans, Asia. They searched for germplasms that could keep plants from weakening and wilting (凋谢)during hot, dry summers in the United States.
Tommy Carter says they found only five. But these slow-wilting lines, he says, produce four to eight bushels(英斗)more than normal soybeans under drought conditions. The yield depends on location and environment.
Scientists are also working on other plants that either use less water or use it better, or both. For example, companies like Monsanto, DuPont and Syngenta have been developing corn with reduced water needs. Monsanto expects to be ready in a few years to market its first corn seeds genetically engineered to resist drought.
1. According to the passage, scientists try to find out how to _______.
A. grow crops with less water
B. increase crop production
C. feed a growing world
D. save the world’s water resource
2. Why did Tommy Carter come to China?
A. He likes traveling.
B. China has a long history.
C. He’s doing research into soybeans.
D. He works for the Agricultural Research Service.
3. What’s inferred from the passage?
A. Climate changes lead to global warming.
B. Water shortages contribute to global warming.
C. Genetically different soybeans need much water to grow.
D. Genetically different soybeans help to fight against damaging climate changes.
4. What do we know about slow-wilting plants talked about in the passage?
A. They yield big profits.
B. They can grow in almost any climate.
C. They seem to be drought-resistant.
D. They need much water for their growth.

科目 英语   题型 阅读理解   难度 较易
登录免费查看答案和解析
相关试题

The Royal Commission on Environmental Pollution has just published a report on new materials and has looked at the case of nanotechnology(纳米技术), which describes the science of the very small. Nanotechnology covers those man-made materials or objects that are about a thousand times smaller than the microtechnology(微电子技术)we use, such as the silicon chips of computers.
Nanotechnology gets its name from the nanometer, which is a billionth of a meter. There are about 600 consumer products already on the market that use nanotechnology. Nanomedicine is also being developed to fight cancer and other fatal diseases.
The Royal Commission found no evidence of harm to health or the environment from nanomaterials, but this “absence of evidence” is not being taken as “evidence of absence”. In other words, just because there are no apparent problems, this is not to say that here is no risk now or in the future. The commission is concerned about the pace at which we are inventing and adopting new nanomaterials, which could result in future problems that we are ill-equipped to understand or even find with current testing methods.
One of the problems about nanotechnology is that when we make something very small out of a well known material, we may actually change the functionality of that material even if the chemical composition remains the same. Indeed, it is not the particle(颗粒)size that should concern us, but its functionality. Take gold, for example, which is a famously inert (惰性) substance, and valuable because of it. It doesn’t rust or corrode because it doesn’t interact with water or oxygen. However, a particle of gold that is between 2 and 5 nanometers in diameter becomes highly reactive. This is not due to a change in chemical composition, but because of a change in the physical size of the gold particles. How can a change in size result in a change of function? One reason is to do with surface area. Nanoparticles have relatively a much bigger surface area. It is like comparing the surface area of a basketball with the total surface area of many pea-sized balls with the same weight of the single basketball. The pea-sized balls have a surface area many hundreds, indeed thousands of times bigger than the basketball, and this allows them to interact more easily with the environment. It is this increased interactivity that changes their functionality—and makes them potentially more dangerous to health or the environment.
Why does the writer mention microtechnology in the first paragraph?

A.to introduce the topic of nanotechnology
B.to help us better understand nanotechnology
C.to help us know more about microtechnology
D.to compare microtechnology with nanotechnology

The example of the “gold” in the last paragraph is intended to show that_________.

A.gold is valuable because it is an inert substance
B.an inert substance like gold doesn’t interact with water or oxygen
C.the function of gold is steady because it is an inert substance
D.the function of gold changes when made into something very small

Which process explains that there might be risks in nanotechnology?

A.expand surface area →increase interactivity → change functionality→cause possible dangers
B.expand surface area → change functionality → increase interactivity →cause possible dangers
C.increase interactivity → expand surface area → change functionality→cause possible dangers
D.increase interactivity → change functionality → expand surface area→cause possible dangers

What does the passage mainly focus on?

A.the introduction of nanotechnology and its wide use
B.the present use of nanotechnology and its future
C.the potential danger nanotechnology may bring us
D.the proposal to stop nanotechnology due to the potential danger

Alone in the wilderness. Nothing but jungle. A world of shadow with the rays of light falling like blonde hair from the crowns of the giant trees. Jungle in the midday sun. Everything motionless. Not a sound from sky or earth. Complete silence. Only some coconuts falling, at long intervals, very far away. The world reduced to the soft touch of cool grass along my naked back, and a sweet smell of rich soil and vegetation. Stretched out with closed eyes beside my heavy burden of fruit and firewood, I enjoyed the feeling of fresh blood streaming through every part of my body and fresh jungle air filling every corner of my lungs.
Resting motionless, I could see the sun through my closed eyelids, alone in the sky, as lonely as I, and as motionless and silent as everything else. The earth had surely stopped turning and somewhere on this planet there was supposed to be roaring traffic in busy streets. What a crazy, unbelievable thought!
Another coconut fell, to make the world come to a complete standstill. I had to roll over onto my stomach to feel that at least I could move and make noises. Then I found company. A little brown ant was struggling to find its way with a bit of dry straw through the jungle of leaves and grass below my nose. I wondered if I could give the little fellow a lift with its burden, but it showed not the slightest sign of tiredness and struggled on with all six legs, head first or head last, waving its feelers energetically as if the trip had just started. Who ever saw a tired ant? Tiredness, disagreeable tiredness, is restricted to hunted animals, slaves and modern man. It is as great an effort for an office clerk to walk five blocks with a loaded brief-case as it is for a jungle-dweller to cross a valley with a goat on his back. It is as hard to get up and climb or run when you have been seated for years as it is to get up and walk when you have been in bed for months. The body is strange. Spare it, and you get really tired for almost nothing; use it, and almost nothing makes you really tired.
I rose to my feet. I had heard a horse neighing down in the valley. Above me, on the open highland plains, there were wild horses. But down in the valley there was never a horse unless there was a man on it. Somebody was making his way up the valley and my wife was alone.
What’s the right order of the following events?
① I heard a horse neighing down in the valley.
② I went to the jungle.
③ I found an ant carrying a bit of dry straw.
④ I lay on the ground to have a break.
⑤ I picked fruits and chopped firewood.

A.②③⑤①④ B.⑤③②④① C.②⑤④③① D.⑤④③②①

How does the author feel about the ant?

A.He admired its attitude toward work.
B.He was amazed at its tireless efforts.
C.He showed sympathy for the little ant.
D.He was content to have it as a companion.

It can be inferred from the last paragraph that the author would probably .

A.work harder than before B.talk to the man on the horse
C.make his way home D.stay in the valley

We can learn from the passage that the author .

A.enjoyed being alone
B.experienced a world of quietness
C.missed his busy life in the city
D.had an unforgettable adventure

Special trees that grow faster, fight pollution, produce better wood, and even sense chemical attacks are being planted by scientists in the US.
When 40 per cent of Hawaii's US$14 million-a-year papaya (木瓜)industry was destroyed by a virus five years ago, work began on creating genetically engineered(转基因的)trees.
Researchers successfully introduced seeds that were designed to resist the virus.Since then, more and more people have been testing genetically engineered trees.Some researchers put special bacteria into trees to help them grow faster and produce better wood.Others are trying to create trees that can clean polluted soil.Meanwhile fruit farmers are looking for trees that are strong enough to resist worms, and paper companies want trees that produce more wood and therefore more paper.
The Pentagon (五角大楼) even gave the researchers US$500,000 this year after they developed a pine tree that changes its colours if it senses a chemical attack.So far, the poplar, eucalyptus (杨树与桉树), apple and coffee trees are among those being engineered.All this can be done today because we have a better understanding of tree genomes (基因组).
However, some people fear that the genetically engineered trees will cause dangerous results.They are worried that the new trees will breed with natural species and change the balance of the forest environment.
“It could be destructive,” said Jim Diamond, an environmentalist. “Trees are what is left of our natural environment and home to many endangered species.”
But researchers insist that science could give nature a fighting chance against both natural and man-made dangers.They hope to answer the critics by stopping the new trees from breeding, so their effect on the environment can be controlled.
Which kind of tree is not the ones that scientists are planting in the US?

A.Trees that worms can't hurt.
B.Genetically engineered trees.
C.Trees that can resist wind better.
D.Trees that can protect themselves at a chemical attack.

What caused the American scientists to work on special trees?

A.Tree genomes are mapped out so scientists know how to improve trees.
B.Great numbers of trees have been lost due to attacks by viruses.
C.Researchers successfully introduced seeds designed to resist the virus.
D.They think science could give nature a fighting chance against both natural and man-made dangers.

Which of the following was probably the first kind of trees being engineered?

A.Papaya. B.Pine. C.Apple. D.Poplar.

Why did critics think engineered trees dangerous? Because ________.

A.these trees can destroy the balance of nature
B.everything except trees has been genetically engineered
C.trees are home to many endangered species
D.these trees may affect normal trees

A device that stops drivers from falling asleep at the wheel is about to undergo(接受) testing at Department of Transport laboratories and could go on sale within 12 months.
The system, called driver Alert, aims to reduce deadly road accidents by 20%--40% that are caused by tiredness. Airline pilots can also use it to reduce the 30% of all pilot-error accidents that are related to fatigue(疲劳).
Driver Alert is based on a computerized wristband. The device, worn by drivers or pilots gives out a sound about every four minutes during a car journey. After each sound the driver must respond by squeezing the steering wheel(方向盘). A sensor in the wristband detects this pressing action and measures the time between the sound and the driver’s response.
Tiredness is directly related to a driver’s response time. Usually, a watchful driver would take about 400 milliseconds to respond, but once that falls to more than 500 milliseconds, it suggests that the driver is getting sleepy.
In such cases the device gives out more regular and louder sounds, showing that the driver should open a window or stop for a rest. If the driver’s response continues to slow down, the sounds become more frequent until a nonstop alarm warns that the driver must stop as soon as possible.
The device has been delivered to the department’s laboratories for testing. If these tests, scheduled for six months’ time, are successful, the makers will bring the product to market within about a year.
How should a driver respond to the sounds from Driver Alert?

A.By sounding a warning.
B.By touching the wristband.
C.By checking the driving time.
D.By pressing the steering wheel.

We can learn from the text that the driver needs to stop for a break when his response time is ________

A.about 400 milliseconds B.below 500 milliseconds
C.over 500 milliseconds D.about 4 minutes

When the driver gets sleepy while driving, Driver Alert ______.

A.moves more regularly
B.stops working properly
C.opens the window for the driver
D.sounds more frequently and loudly

According to the text, Driver Alert ______.

A.aims to reduce tiredness-related accidents
B.has gone through testing at laboratories
C.aims to prevent drivers from sleeping
D.has been on sale for 12 months

Sports can help you keep fit and get in touch with nature.However, whether you are on the mountains, in the waves, or on the grassland, you should be aware that your sport of choice might have great influence on the environment.
Some sports are resource-hungry.Golf, as you may know, eats up not only large areas of countryside, but also tons of water.Besides, all sorts of chemicals and huge amounts of energy are used to keep its courses (球场) in good condition.This causes major environmental effects.For example, in the dry regions of Portugal and Spain, golf is often held responsible for serious water shortage in some local areas.
There are many environment-friendly sports.Power walking is one of them that you could take up today.You don’t need any special equipment except a good pair of shoes; and you don’t have to worry about resources and your purse.Simple and free, power walking can also keep you fit.If you walk regularly, it will be good for your heart and bones.Experts say that 20 minutes of power walking daily can make you feel less anxious, sleep well and have better weight control.
Whatever sport you take up, you can make it greener by using environment-friendly equipment and buying products made from recycled materials.But the final goal should be “green gyms”.They are better replacements for traditional health clubs and modern sports centers.Members of green gyms play sports outdoors, in the countryside or other open spaces.There is no special requirement for you to start your membership.And best of all, it’s free.
The author thinks the golf is resource-hungry because of the following EXCEPT that ________.

A.Golf wastes large areas of countryside
B.Golf runs out of much water
C.Golf is bad for people’s health
D.Keeping golf court in good condition needs too much energy

According to the passage, which of the following is an environment-friendly sport?

A.hiking in the hills B.swimming in the pool
C.playing basketball in the gym D.motor racing in the desert

The reason why the author uses power walking as an example mainly is that ________.

A.it improves our health B.it is an outdoor sport
C.it is recommended by experts D.it uses fewer resources

The passage is developed mainly by ________.

A.examples and explanation B.comparison and persuasion
C.facts and descriptions D.figures and conclusion

Copyright ©2020-2025 优题课 youtike.com 版权所有

粤ICP备20024846号