Have you ever wondered why the roots of the plants always know which way to grow—into the soil but not above it? Some British scientists have recently solved this mystery.
It turns out that roots have special hairs that tie them into the soil and help them grow their way past obstacles, a team at the John Inners Center in Norwich reports in the February 29 issue of Journal Science.
“The key is in the fuzzy(有绒毛的)coat of hairs on the roots of plants,” says professor Liam Dolan. “We have found a growth control system that enables these hairs to find their way and to become longer when their path is clear.”
Root hairs explore the soil in much the same way a person would feel their way in the dark. If they come across an obstacle, they make their way around until they can continue growing in an opening. In the meantime, the plant is held in place as the hairs grip(紧紧抓住)the soil.
The hairs are guided by a clever chemical trick. A protein(蛋白质) at the tip of the root hairs called RHD2 helps them to take calcium(钙) from the soil. Calcium makes the hairs grow, and produce more RHD2, and take more calcium.
But when an obstacle blocks the hair’s path, or the hair reaches the surface of the soil, the cycle is broken and growth starts in another direction.
This system gives plants the flexibility to explore a complex environment and to live in even the most unpromising soils, says Dolan.
In poor soils such as in parts of Australia and Africa, native plants have adapted by producing enormous numbers of root hairs. A better understanding of this adaptation will allow scientists to develop hairy rooted crops that can grow in unfriendly environments.
According to Dolan, “Research in the John Inners Center is taking a breeding approach to increase hair length in wheat but it will be some time before new cultivars(栽培变种) are developed.”The passage is mainly about _______.
| A．why the roots of plants grow into the soil but not above it |
| B．how the roots of plants grow into the soil but not above it |
| C．the process of plants growth |
| D．a growth control system of plants |
How does the circle work?
| A．RHD2 takes calcium from the soil, which makes hairs grow, and produce RHD2 and take more calcium |
| B．Roots take RHD2 and calcium from the soil and produce RHD2 |
| C．Roots make hairs grow, and produce RHD2, and take more calcium |
| D．RHD2 takes protein, which makes hairs grow, and produce RHD2, and take more calcium |
We can infer from the last paragraph that ________.
| A．hairy rooted crops can grow better in unfriendly environments |
| B．a new cultivar of wheat with long hair has been developed by scientists |
| C．a new cultivar of wheat with long hair is still on test |
| D．the roots of plants always know which way to grow |
We can make mistakes at any age. Some mistakes we make are about money. But most mistakes are about people. "Did Jerry really care when I broke up with Helen? "When I got that great job, did Jim really feel good about it, as a friend? Or did he envy (嫉妒) my luck?" "And Paul-why didn't he pick up that he was friendly just because I had a car?" When we look back, doubts like these can make us feel bad. But when we look back, it's too late.
Why do we go wrong about our friends - or our enemies? Sometimes what people say hides their real meaning. And if we don't really listen we miss the feeling behind the words. Suppose someone tells you, “You're a lucky dog." that's being friendly. But "lucky dog"? There's a bit of envy in those words. Maybe he doesn't see it himself. But bringing in the "dog" bit puts you down a little. What he may be saying is that he doesn't think you deserve your luck.
"Just think of all the things you have to be thankful for" is another noise that says one thing and means another. It could mean that the speaker is trying to get you to see your problem as part of your life as a whole. But is he? Wrapped up (包藏) in this phrase is the thought that your problem isn't important. It's telling you to think of all the starving people in the world when you haven't got a date for Saturday night.
How can you tell the real meaning behind someone's words? One way is to take a good look at the person talking. Do his words fit the way he looks? Does what he says agree with the tone of voice? His posture (姿态)? The look in his eyes? Stop and think. The minute you spend thinking about the real meaning of what people to you may save another mistake.This passage is mainly about ____.
| A．how to interpret what people say |
| B．what to do when you listen to others talking |
| C．how to avoid mistakes when you communicate with people |
| D．why we go wrong with people sometimes |
According to the author, the reason why we go wrong about our friends is that ____
| A．we fail to listen carefully when they talk | B．we tend to doubt what our friends say |
| C．people usually state one thing but means another | |
| D．people tend to be annoyed when we check what they say |
In the sentence "Maybe he doesn't see it himself." In the second paragraph, the pronoun “it” refers to _____
| A．being friendly | B．a bit of envy | C．lucky dog | D．your luck |
When we listen to a person talking, the most important thing for us to do is____.
| A．notice the way the person is talking | B．take a good look at the person talking |
| C．mind his lone, his posture and the look in his eyes | |
| D．examine the real meaning of what he says based on his manner, his tone and his posture |
Excused from recycling(回收利用) because you live in a high rise with a rubbish chute (垃圾道)? You won't be for long. Miami's Mark Shantzis has made it simple for those living in tall buildings to use the chute and recycle too .
In Shantzis' Hi-Rise Recycling System, a chute leads to a pie-shaped container with six boxes that can turn around when operated. The system , which fits in the same space as the chute and container now in use, enables glass , plastic , paper , metal , and other rubbish to go into separate boxes .
The system is controlled from a board next to the chute door. The board has a button for each class of recycling materials (as well as for unrecyclables). At the press of a button, a microcomputer locks all other floors' chute door and sets the recycling container turning until the right box comes under the chute. The computer also counts the loads and gives a signal by phone when the box is full. And a particular piece of equipment breaks up the nonrecyclables
Sorting(分类) recyclables before they are collected saves the use of expensive materials recovery equipment which otherwise has to do the sorting . Such equipment often makes recycled materials very expensive, so expensive that tons of recyclables remain wasted . Shantzis believes his system could help recycled materials become more cost-effective.The purpose in writing this text is _________.
| A．to encourage people to recycle their rubbish |
| B．to introduce a recycling system for high rises |
| C．to describe the use of computer technology in recycling |
| D．to explain the need for rubbish collection in high rises |
When he says "You won't be for long" the writer means that _______.
| A．you'll soon be living in a cleaner building |
| B．rubbish chutes will become out of date before long |
| C．you won't wait long for your turn to recycle rubbish |
| D．it won't be long before you'll have to recycle your rubbish |
Before dropping rubbish into the chute you have to ___________
| A．lock the other floors' chute doors | B．check if the container is full |
| C．press the correct button | D．break up the rubbish |
The biggest advantage of this new system is that _________
| A．it reduces the cost of recycling | B．it saves time and space |
| C．it saves money for people living in high rises | |
| D．it makes better use of the existing recovery equipment |
Money spent on advertising is money spent as well as any I know of. It serves directly to bring about a rapid sale of goods at reasonable prices, so setting up a firm home market and making it possible to provide for export (出口) at good prices. By drawing attention to new ideas it helps greatly to raise standards of living. By helping to increase demand it causes an increased need for labour, and is therefore a nice way to fight unemployment. It lowers the costs of many services: without advertisements your daily newspaper would cost four times as much, the price of your television program would need to be doubled, and travel by bus or subway would cost more.
And perhaps most important of all, advertising provides a promise of reasonable value in the products and services you buy. Besides the fact that twenty-seven Acts of Parliament(国会)govern the terms of advertising, no regular advertiser dare produce anything that fails to live up to the promise of his advertisements. He might fool some people for a little while through misleading advertising. He will not do so for long, for the public has the good sense not to buy the poor goods more than once. If you see product frequently advertised, it is the proof I know that the product does what is promised for it, and that it has good value.
Advertising does more for the good of the public than any other force I can think of.
There is one more point I feel I ought to touch on. Recently I heard a well-known television person declared that he was against advertising because it persuades rather than informs. He was telling us the real difference. Of course advertising tries to persuade.
If its message were nothing but information, that would be difficult to get more people to buy, for even the choice of the colour of a shirt is a bit persuasive (有说服力的)--advertising would be so boring that no one would pay any attention. But perhaps that is what the well-known television person wants.By the first sentence of the passage the writer means that ___.
| A．he is fairly familiar with the cost of advertising |
| B．everybody knows well that advertising is a waste of money |
| C．advertising costs more money than everything else |
| D．money on advertising is worth spending |
In the passage, which of the following is NOT included in the advantages of advertising?
| A．Getting greater fame. | B．Providing more jobs. |
| C．Raising living standards. | D．Reducing newspaper cost. |
The writer thinks that the well-known TV person is _____.
| A．quite right in passing his judgment on advertising |
| B．interested in nothing but the buyers' attention |
| C．correct in telling the difference between persuasion and information |
| D．obviously unfair in his views on advertising |
In the writer's opinion, ________.
| A．advertising can seldom bring material interest to man by providing information |
| B．advertising informs people of new ideas rather than wins them over |
| C．there is nothing wrong with advertising in persuading the buyer |
| D．the buyer is not interested in getting information from an advertisement |
Forty years ago, Rachel Carson died and the Pittsburgh area lost perhaps its most influential citizen. A native of a Pennsylvania College for Women graduate, Carson published “Silent Spring” in 1962, a work that launched the modern environmental movement and led to the creation of the Environmental Protection Agency (EPA) as well as the passage of our major environmental laws.
However, there has been a puzzling and troubling trend in recent years: an attack on her theory by conservatives and the agrochemical (农用化学品) industry. For example, Rush Limbaugh gave the following quiz: “Who caused more deaths: Adolf Hitler or RachelCarson?” Limbaugh's answer was Carson, due to the approximately 100 million deaths from malaria (疟疾) since 1972, the year in which the pesticide (杀虫剂）DDT was banned for use in the United States in part as a result of “Silent Spring.”
Therefore, on this 40th anniversary of Carson's death, we need to take a scientific look at the myths that remain about pesticides.
Myth 1: Pesticide usage has declined since 1962. In fact, pesticide usage has more than doubled since 1962, and the global pesticide industry currently uses over 2.5 million tons of pesticides each year. Even DDT is still used abroad.
Myth 2: Pesticides are safe. In fact, as Carson warned us, these poisonous chemicals are unsafe since they are designed to kill biological organisms, but are often not specific in their targets. Pesticide exposure can cause skin irritation, headache, cancer and even death. According to the WHO, over 25 million people a year in developing countries suffer severe acute pesticide poisonings with over 20,000 deaths.
Of the 80,000 pesticides and other chemicals in use today, 10 percent are recognized as carcinogens (致癌物质). According to recent studies, brain cancer rates are five times higher in homes with “no-pest” strips and six times higher in homes where pets wear flea collars (杀蚤颈圈). Our homes have pesticide concentrations 10 to 100 times higher than outdoors.
So, if Carson were with us today, still battling the agrochemical industry that spent millions of dollars, what would she be advocating? I feel confident that she would be a strong supporter of a new principle of chemical assessment. 
Simply put, this principle requires producers of pesticides to prove that they are safe and necessary before they are put on the market. Our current system puts the burden of proof on government and scientists to prove that a pesticide is dangerous and poses an “unacceptable risk” before it can be pulled from the market.
57. Limbaugh attacked Carson because he thought that _____.
A. “Silent Spring” had caused in part the 100 million deaths from malaria
B. she was supporting the production of poisonous pesticides
C. “Silent Spring” was originated from Hitler’s writings
D. she had not cared for the 100 million deaths from malaria
58. Which of the following is the content of Myth 1?
A. The production of pesticides has doubled during the past 40 years.
B. 2.5 million tons of pesticides have been produced since 1962.
C. The usage of pesticides has been dropping since 1962.
D. Pesticides have become less poisonous since 1962.
59. The author mentions “flea collars” in the sixth paragraph to indicate _____.
A. pesticides contribute to the development of cancer
B. the close connection between them and dog cancer rates
C. the medical effect of flea collars on dogs
D. flea collars contribute to high pesticide concentrations indoors
60. What is the suggested new practice of chemical assessment?
A. Government should prove a pesticide is unsafe.
B. Scientists should be responsible for writing assessment reports.
C. Producers of pesticides should provide proof of their safety.
D. A special committee should be set up for chemical assessment.
About six years ago I was eating lunch in a restaurant in New York City when a woman and a young boy sat down at the next table. I couldn’t help overhearing parts of their conversation. At one point the woman asked: “So, how have you been?” And the boy, who could not have been more than seven or eight years old, replied, “Frankly, I’ve been a little depressed lately.”
This incident stuck in my mind because it confirmed my growing belief that children are changing. As far as I can remember, my friends and I didn’t find out we were “depressed” until we were in high school.
The evidence of a change in children has increased steadily in recent years. Children don’t seem childlike anymore. Children speak more like adults, dress more like adults and behave more like adults than they used to.
Whether this is good or bad is difficult to say, but it certainly is different. Childhood as it once was no longer exists, why?
Human development is based not only on innate(天生) biological states, but also on patterns of access to social knowledge. Movement from one social rote(生搬硬套) to another usually involves learning the secrets of the new status. Children have always been taught adult secrets, but slowly and in stages: we tell sixth graders things we keep hidden from fifth graders.
In the last 30 years, however, a secret-revelation(揭示) machine has been brought in 98 percent of American homes. It is called television. Television passes information to all viewers alike, indiscriminately (不加区分地). Unable to resist the temptation, many children turn their attention from printed texts to the less challenging, more vivid moving pictures.
Communication through print, as a matter of fact, allows for a great deal of control over the social information to which children have access. Reading and writing involve a complex code of symbol that must be memorized and practices. Children must read simple books before they can read complex materials.
53. Traditionally, a child is supposed to learn about the adult world______________.
A. through contact with society
B. naturally and by biological instinct (本能)
C. gradually and under guidance
D. through exposure to social information
54. The phenomenon that today’s children seem adult like is due to ____________.
A. the widespread influence of television
B. the poor arrangement of teaching content
C. the fast pace of human intellectual development
D. the constantly rising standard of living
55. Why is the author in favor of communication through print for children?
A. It enables children to gain more social information.
B. It develops children’s interest in reading and writing.
C. It helps children to memorize and practice more.
D. It can control what children are to learn.
56. What does the author think of the change in today’s children?
A. He feels amused by their premature (早熟) behavior.
B. He thinks it is a phenomenon worthy of note.
C. He considers it a positive development.
D. He seems to be upset about it.