Which animal has the fastest snapping jaw (颚)? If you're guessing a shark or perhaps a larger animal, you'll have to think smaller. The trapjaw ant, which lives in Central and South America, moves its mouth parts at 35 to 63 meters per second. Another way to think about this is that the ant's jaws close at 125 to 233 kilometers per hour. That's 2, 300 times faster than the blink of an eye.
Scientists were able to measure the amazing jaw speed using highspeed video techniques. Sheila Patek, a biologist, says the key is that the jaws have a springy (有弹性的) system, which is critical in getting explosive (爆发性的) speeds.
Consider a bow and arrow. If you try to throw an arrow with your arm, it won't go very far. If you use a bow, elastic energy stored in the bow is released almost instantly when you release the arrow with your finger or a latch. The combination of the springy bow and latch mechanism is what makes the arrow zoom through the air.
Maybe even more amazing than how fast these ants grab food or even enemies is how they use this same energy to move. As the ant closes its jaws, it uses them to push off the ground—all faster than the eye can see without slow motion video. A snap of the jaw can send an ant up to 8.3 centimeters into the air. That's like someone who is 1.7 meters jumping 13 meters high! Not only can they quickly escape from enemies, but often a group of ants will start jumping all at once. It would be hard for their enemies to grab just one.
People have suspected the ants used their jaws to jump for over a century, but could only prove it with today's modern video equipment.The fast speed of the trapjaw ant's jaw lies in ________.
| A．its light body |
| B．its springy system |
| C．its living environment |
| D．the length of its jaw |
The passage uses “a bow and arrow” as an example to show ________.
| A．how an arrow gets so much energy to fly |
| B．why the trapjaw ants have springy system |
| C．why the trapjaw ants jaws move so fast |
| D．how a bow and arrow works |
Which of the following may amaze the scientists most?
| A．How high the ants can leap by using their jaws. |
| B．How quickly the trapjaw ants can move on the ground. |
| C．How wonderfully the springy system in the trapjaw ants' jaws works. |
| D．How quickly the trapjaw ants can grab food or enemies. |
According to the passage, the trapjaw ants' jaws keep them safe because ________.
| A．they can catch their enemies easily with their jaws |
| B．their jaws make them difficult to recognize |
| C．their jaws help them find food easily |
| D．their jaws help them escape from their enemies |
Even plant can run a fever, especially when they’re under attack by insects or disease. But unlike human, plants can have their temperature taken from 3, 000 feet away straight up. A decade ago, adopting the infrared （红外线）scanning technology developed for military purposes and other satellites, physicist Stephen Paley came up with a quick way to take the temperature of crops to determine which ones are under stress. The goal was to let farmers precisely target pesticide （杀虫剂）spraying rather than rain poison on a whole field, which invariably includes plants that don’t have pest （害虫）problems.
Even better, Paley’s Remote Scanning Services Company could detect crop problems before they became visible to the eye. Mounted on a plane flown at 3, 000 feet at night, an infrared scanner measured the heat emitted by crops. The data were transformed into a color-coded map showing where plants were running“fevers”. Farmers could then spot-spray, using 50 to 70 percent less pesticide than they otherwise would.
The bad news is that Paley’s company closed down in 1984, after only three years. Farmers resisted the new technology and long - term backers were hard to find. But with the renewed concern about pesticides on produce, and refinements in infrared scanning, Paley hopes to get back into operation. Agriculture experts have no doubt the technology works. “This technique can be used on 75 percent of agricultural land in the United States, ” says George Oerther of Texas A & M. Ray Jackson , who recently retired from the Department of Agriculture, thinks remote infrared crop scanning could be adopted by the end of the decade. But only ff Paley finds the financial backing which he failed to obtain 10 years ago. Plants will emit an increased amount of heat when they are______________.
| A．sprayed with pesticides |
| B．facing an infrared scanner |
| C．in poor physical condition |
| D．exposed to excessive sun rays |
．In order to apply pesticide spraying precisely, we can use infrared scanning to____________.
| A．estimate the damage to the crops |
| B．measure the size of the affected area |
| C．draw a color-coded map |
| D．locate the problem area |
Farmers can save a considerable amount of pesticide by______________.
| A．resorting to spot-spraying |
| B．consulting infrared scanning experts |
| C．transforming poisoned rain |
| D．detecting crop problems at an early stage |
The application of infrared scanning technology to agriculture met with some difficulties
_______________.
| A．the lack of official support |
| B．its high cost |
| C．the lack of financial support |
| D．its failure to help increase production |
Infrared scanning technology may be brought back into operation because of_____________.
| A．the desire of farmers to improve the quality of their produce |
| B．growing concern about the excessive use of pesticides on crops |
| C．the forceful promotion by the Department of Agriculture |
| D．full support from agricultural experts |
An idea that started in Seattle's public library has spread throughout America and beyond. The concept is simple: help to build a sense of community in a city by getting everyone to read the same book at the same tome.
In addition to encouraging reading as a pursuit (追求) to be enjoyed by all, the program allows strangers to communicate by discussing the book on the bus, as well as promoting reading as an experience to be shared in families and schools. The idea came from Seattle librarian Nancy Pearl who launched (发起）the "If All of Seattle Read the Same Book " project in 1998. Her original program used author visits, study guides and book discussion groups to bring people together with a book, but the idea has since expanded to many other American cities, and even to Hong Kong.
In Chicago, the mayor(市长）appeared on television to announce the choice of To Kill a Mockingbird as the first book in the "One Book, One Chicago" program. As a result, reading clubs and neighbourhood groups sprang up around the city. Across the US, stories emerged of parents and children reading to each other at night and strangers chatting away on the bus about plot and character.
The only problem arose in New York, where local readers could not decide on one book to represent the huge and diverse population. This may show that the idea works best in medium-sized cities or large towns, where a greater sense of unity(一致）can be achieved .Or it may show that New Yorkers rather missed the point ,putting all their energy
And passion into the choice of the book rather than discussion about a book itself.
Ultinatel was Nancy points out, the level of success is not measured by how many people read a book, but by how many people are enriched by the process. or have enjoyed speaking to someone with whom they would not otherwise have shared a word. What is the purpose of the project launched by Nancy?
| A．To invite authors to guide readers. |
| B．To encourage people to read and share. |
| C．To involve people in community service. |
| D．To promote the friendship between cities. |
Why was it difficult for New Yorkers to carry out the project?
| A．They had little interest in reading. |
| B．They were too busy to read a book. |
| C．They came from many different backgrounds |
| D．They lacked support from the local government |
According to the passage, where would the project be more easily carried out?
| A．In large communities with little sense of unity |
| B．In large cities where libraries are far from home |
| C．In medium-sized cities with a diverse population |
| D．In large towns where agreement can be quickly reached |
The underlined words “shared a word” in Paragraph 5 probably mean
| A．exchanged ideas with each other |
| B．discussed the meaning of a word |
| C．gamed life experience |
| D．used the same language |
According to Nacy, the degree of students of the project is judged by
the careful selection of a proper book
the growing popularity of the writers
C. the number of people who benefit from reading.
D. the number of books that each person reads.
An idea that started in Seattle's public library has spread throughout America and beyond. The concept is simple: help to build a sense of community in a city by getting everyone to read the same book at the same tome.
In addition to encouraging reading as a pursuit (追求) to be enjoyed by all, the program allows strangers to communicate by discussing the book on the bus, as well as promoting reading as an experience to be shared in families and schools. The idea came from Seattle librarian Nancy Pearl who launched (发起）the "If All of Seattle Read the Same Book " project in 1998. Her original program used author visits, study guides and book discussion groups to bring people together with a book, but the idea has since expanded to many other American cities, and even to Hong Kong.
In Chicago, the mayor(市长）appeared on television to announce the choice of To Kill a Mockingbird as the first book in the "One Book, One Chicago" program. As a result, reading clubs and neighbourhood groups sprang up around the city. Across the US, stories emerged of parents and children reading to each other at night and strangers chatting away on the bus about plot and character.
The only problem arose in New York, where local readers could not decide on one book to represent the huge and diverse population. This may show that the idea works best in medium-sized cities or large towns, where a greater sense of unity(一致）can be achieved .Or it may show that New Yorkers rather missed the point ,putting all their energy
And passion into the choice of the book rather than discussion about a book itself.
Ultinatel was Nancy points out, the level of success is not measured by how many people read a book, but by how many people are enriched by the process. or have enjoyed speaking to someone with whom they would not otherwise have shared a word. What is the purpose of the project launched by Nancy?
| A．To invite authors to guide readers. |
| B．To encourage people to read and share. |
| C．To involve people in community service. |
| D．To promote the friendship between cities. |
.Why was it difficult for New Yorkers to carry out the project?
| A．They had little interest in reading. |
| B．They were too busy to read a book. |
| C．They came from many different backgrounds |
| D．They lacked support from the local government |
According to the passage, where would the project be more easily carried out?
| A．In large communities with little sense of unity |
| B．In large cities where libraries are far from home |
| C．In medium-sized cities with a diverse population |
| D．In large towns where agreement can be quickly reached |
The underlined words “shared a word” in Paragraph 5 probably mean
| A．exchanged ideas with each other |
| B．discussed the meaning of a word |
| C．gamed life experience |
| D．used the same language |
According to Nacy, the degree of students of the project is judged by
the careful selection of a proper book
the growing popularity of the writers
C. the number of people who benefit from reading.
D. the number of books that each person reads.
Development of a widely accepted chronology for the arrival of humans has been equally difficult, and it was only with the development of optically stimulated luminescence dating that a human presence in Australia was confirmed at 53,000 to 60,000 years ago. Older dates for a human presence in Australia have now been shown to be erroneous .
The importance of Australia as a separate natural laboratory in which to test extinction theories lies in the fact that humans arrived there much earlier than they arrived in the other continental areas (the Americas and northern Eurasia) that experienced substantial megafaunal extinction. What Miller et al. have shown is that the extinction of Genyornis occurred simultaneously across southeastern Australia (indeed probably right across the continent) about 50,000 years ago. This is very close to the presently accepted time of arrival of humans in Australia. It was also a period of modest climate change, well before the dramatic climatic fluctuations of the terminal Pleistocene. The data of Miller et al., therefore, support those who see human hunting rather than climate as causing the extinction of the megafauna.
Genyornis was a ponderous bird, around 80 to 100 kg in weight, about twice as heavy as the living emu and cassowary. It was an inhabitant of Australias inland plains and some coastal regions, but its legs were relatively short and thick, suggestion that it was a slower runner than the emu. Proponents of humancaused extinction suggest that it is just such characteristics that made the megafauna vulnerable to human hunting.
A new school of thought has recently established itself in the extinction debate. It advocates the idea that a combination of human impact and climate change was responsible for the extinction of the worlds megafauna. The new Genyornis data also weaken that argument, for the following reason. Fifty thousand years ago, Australia was experiencing mild cooling; 11,000 to 12,000 years ago, the Americas were experiencing rapid warming. These disparate climatic conditions, all coincident with megafaunal extinction, suggest that whatever was happening with climate, it was bad for the big animals. Under these conditions, the hybrid model becomes indistinguishable from the humancaused extinction model for the influence of climate becomes extremely weak, and only the arrival of humans is important in predicting extinction. The last word “megafauna” in Paragraph 2 most probably means
A birds. B plants.
C big animals. D small animals. Genyornis was vulnerable to human hunting because it was
A a delicacy. B very weak.
C very small in size. D clumsy. How many models have been put forward for the extinction of Genyoris?
A One. B Two.
C Three. D Four. That Australia experienced mild cooling and the Americas rapid warming suggests that
A the climatic conditions were unfit for Genyornis to live.
B Genyornis were highly adaptable to different climatic conditions.
C The two climatic conditions were both bad for Genyornis.
D The climatic conditions had nothing to do with the extinction of Genyoris. The selection is mainly about
A the debate over the time of the human presence in Australia.
B the relationship between the human presence and magafaunal extinction.
C the relationship between human activities and climatic changes.
D the debate over factors causing megafaunal extinction.
It was Saturday. As always, it was a busy one, for “Six days shall you labor and do all your work” was taken seriously back then. Outside, Father and Mr. Patrick next door were busy chopping firewood. Inside their own houses, Mother and Mrs. Patrick were engaged in spring cleaning.
Somehow the boys had slipped away to the back lot with their kites. Now, even at the risk of having Brother caught to beat carpets , they had sent him to the kitchen for string(线). It seemed there was no limit to the heights to which kites would fly today.
My mother looked at the sitting room, its furniture disordered for a thorough sweeping, A gun she cast a look toward the window. “Come on, girls! Let’s take string to the boys and watch them
On the way we met Mrs. Patrick, laughing guiltily as if she were doing something wrong, together with her girls.
There never was such a day for flying kited! We played all our fresh string into the boys’ kites and they went up higher and higher .We could hardly distinguish the orange-colored spots of the kites. Now and then we slowly pulled one kite back, watching it dancing up and down it the wind, and finally bringing it down to earth, just for the joy of sending it up again.
Even our fathers dropped their tools and joined us. Our mothers took their turn, laughing like schoolgirls. I think we were all beside ourselves. Parents forgot their duty and their dignity; children forgot their everyday fights and little jealousies. “Perhaps it’s like this in the kingdom of heaven,” I thought confusedly.
It was growing dark before we all walked sleepily back to house. I suppose we had some sort of supper. I suppose there must have been a surface tidying-up, for the house on Sunday looked clean and orderly enough. The strange thing was, we didn't mention that day afterward. I felt a little embarrassed .Surely none of the others had been as excited as I. I locked the memory up in that deepest part of me where we keep “the things that cannot be and yet they are.”
The years went on, then one day I was hurrying about my kitchen in a city apartment, trying to get some work out of the way while my three-year-old insistently cried her desire to “go park ,see duck.”
“I can’t go!” I said. “I have this and this to do, and when I’m through I’ll be too tired to walk that for.”
My mother , who was visiting us , looked up from the peas she was shelling ,“It’s a wonderful day,” she offered，“Really warm , yet there’s a fine breezy . Do you remember that day we flew kites?”
I stopped in my dash between stove and sink. The looked door flew open and with it a rush of memories. “Come on.” I told my little girl. “You’re right, it’s too good a day to miss.”
Another decade passed. We were in the aftermath (余波)of a great war. All
evening we had been asking our returned soldier, the youngest Patrick Boy, about his experiences as a prisoner of war. He had talked freely, but now for a long time he had been silent. What was he thinking of – what dark and horrible things?
“Say!” A smile slipped out from his lips. “Do you remember --- no, of course you wouldn’t. It probably didn’t make the impression on you as it did on me.”
I hardly dared speak. “Remember what?”
“I used to think of that day a lot in POW camp(战俘营), when things weren’t too good. Do you remember the day we flew the kites?” Mrs. Patrick was laughing guiltily because she thought .
| A．she was too old to fly kites |
| B．her husband would make fun of her |
| C．she should have been doing her housework then |
| D．her girls weren’t supposed to play the boy’s game |
By” we were all beside ourselves”, the writer means that they all .
| A．felt confused | B．went wild with joy |
| C．looked on | D．forgot their fights |
What did the writer think after the kite-flying?
| A．The boys must have had more fun than the girls. |
| B．They should have finished their work before playing. |
| C．Her parents should spend more time with them. |
| D．All the others must have forgotten that day. |
Why did the writer finally agree to take her little girl for an outing?
| A．She suddenly remembered her duty as a mother. |
| B．She was reminded of the day they flew kites. |
| C．She had finished her work in the kitchen. |
| D．She thought it was a great day to play outside. |
The youngest Patrick Boy is mentioned to show that _____ .
| A．the writer was not alone in treasuring her fond memories |
| B．his experience in POW camp threw a shadow over his life |
| C．childhood friendship means so much to the writer |
| D．people like him really changed a lot after the war |
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