題目列表(包括答案和解析)
A recent study of ancient and modern elephants has come up with the unexpected conclusion
that the African elephant is divided into two distinct (不同的) species.
The discovery was made by researchers at York and Harvard Universities when they were
examining the genetic relationship between the ancient woolly mammoth and mastodon to
modern elephants-the Asian elephant, African forest elephant,and African savanna elephant.
Once they obtained DNA sequences (序列) from two fossils (化石), mammoths and mastodons,
the team compared them with DNA from modern elephants.They found to their amazement that modern forest and savanna elephants are as distinct from each other as Asian elephants and
mammoths.
The scientists used detailed genetic analysis to prove that the African savanna elephant and
the African forest elephant have been distinct species for several million years.The divergence
of the two species took place around the time of the divergence of Asian elephants and woolly
mammoths.This result amazed all the scientists.
There has long been debate in the scientific community that the two might be separate
species, but this is the most convincing scientific evidence so far that they are indeed different
species.
Previously, many naturalists believed that African savanna elephants and African forest
elephants were two populations of the same species, despite the elephants' significant size
differences.The savanna elephant has an average shoulder height of 3.5 metres while the forest elephant has an average shoulder height of 2.5 metres.The savanna elephant weighs between six and seven tons, roughly double the weight of the forest elephant.But the fact that they look so
different does not necessarily mean they are different species.However the proof lay in the
analysis of the DNA.
Alfred Roca, assistant professor in the Department of Animal Sciences at the University of
Illinois, said, "We now have to treat the forest and savanna elephants as two different units for
conservation purposes.Since 1950, all African elephants have been conserved as one species.
Now that we know the forest and savanna elephants are two very distinctive animals, the forest elephant should become a bigger priority(優(yōu)先) for conservation purposes."
A. The conservation of African elephants.
B. The purpose of studying African elephants.
C. The way to divide African elephants into two units.
D. The reason for the distinction of African elephants.
| 完形填空。 | |||
| When I was thirteen, my family moved from Boston to Tucson, Arizona. __2__the move, my father __2__us in the living-room on a freezing January night. My sisters and I sat around the fire, not __3__ that the universe would suddenly change its course. "In May, we are__4__ to Arizona." The words, so small, didn't seem__5__enough to hold my new life. But the world changed and I awoke on a tram moving across the country.1 watched the __6__change from green trees to flat dusty plains to high mountains as I saw strange new plants that __7__ mysteries yet to come. Finally, we arrived and __8__ into our new home. __9__ my older sisters were sad at the loss of friends, I _10_explored our new surroundings. One afternoon, I was out exploring __11__ and saw a new kind of cactus(仙人掌). I crouched(蹲)down for a closer look. "You'd better not __12__ that" I turned around to see an old woman. "Are you new to this neighborhood?" I explained that I was, __13__,new to the entire state． "My name is Ina Thorne." Have you got used to life in the __14__? It must be quite a __15__ after living in Boston." How could I explain how I __16__ the desert? I couldn't seem to find the right words. "It's vastness," she offered. "That vastness __17__ you stand on the mountains overlooking the desert-you can __18__ how little you are in comparison with the world. __19__, you feel that the possibilities are limitless." That was it. That was the feeling I'd had ever since I'd first seen the mountains of my new home. Again, my __20__ would change with just a few simple words. "Would you like to come to my home tomorrow?" Someone should teach you which plant you should and shouldn't touch." | |||
| ( )1.A.During ( )2.A.gathered ( )3.A.hoping ( )4.A.going ( )5.A.good ( )6.A.picture ( )7.A.suggested ( )8.A.settled ( )9.A.If ( )10.A.bitterly ( )11.A.aswell ( )12.A.move ( )13.A.ofcourse ( )14.A.desert ( )15.A.luck ( )16. A.found ( )17.A.why ( )18.A.prove ( )19.A.However ( )20.A.idea |
B.Until |
C.Upon C.organized C.realizing C.driving C.big C.scene C.discovered C.hurried C.Once C.proudly. C.rightaway C.pull C.afterall C.state C.shock C.watched C.how C.sense C.Therefore C.home |
D.Before D.comforted D.believing D.flying D.proper D.area D.explained D.stepped D.While D.eagerly D.ontime D.touch D.atleast D.country D.danger D.reached D.where D.expect D.Meanwhile D.family |
Jane was dressed in red ______ Joe was dressed in blue.
|
A．however |
B．when |
C．while |
D．a(chǎn)s |
"Extra? Extra！Gasoline hits four dollars a gallon!”
??? No one will really be shocked一except, perhaps, the old-timers who tell about the good old days when gas was three gallons for a dollar, and people drove around "just for the fun of it".
As a matter of fact; the price of gas has been rising fast and steadily for several years, and many adjustments have already been made.
??? There was, for a time, considerable unemployment in the auto industry, and three quarters of the garages and service stations have gone out of business. However; the bicycle and motor-scooter business has flourished（興旺); and many people have found employment there: Now that Federal Motors has brought out its new Lilliput, which travels forty miles on a gallon, the auto business is picking up again. The factories that haven't switched over to two-wheel transportation are working on their new smaller models. There is talk, too, about bringing out new steam and electric automobiles that will be just as economical as the old cars.
??? In the meantime, streetcars are gradually replacing buses all over the country because of the greater economy of electric power. And many people who have seldom used public transportation are now riding the streetcars while their automobiles rust（生銹）in their garages. There's no market at all for their big, luxurious cars, for only the wealthy can now afford to operate them. Many people are now shopping in their own neighborhood, and small businesses are thriving.
??? Ministers, educators, and editorial writers are pointing out that there has been a great improvement in family life. Families now stay at home more for their fun, and children and parents are becoming better acquainted. The stores report a booming business in parlor games, hobby materials, books, musical instruments and albums.
??? People have lost their pale indoor look. The revival of the lost art of walking has brought a healthy pink back to many a cheek. This return to the heels has revolutionized the clothing styles; people now need to be ready for all kinds of weather:
??? These conditions, however, may not last. Already our clever chemists are at work on new synthetic fuels which, they say, will put us right back where we were一on wheels. Shall w e wish them success or not?
1.Which of the following is NOT a result of the gas price rising?
A. More people prefer to travel on public transportation which costs less than driving cars.
B. People return to the traditional exercise of walking, which helps them to look healthier.
C. People shop in nearby stores without having to drive, so small businesses are declining.
D. The auto industry has been forced to develop new models which are more economical.
2.The purpose of writing this passage is＿．
A. to show the chain reaction of the rising gas price
B. to discuss whether it's necessary to work on new fuels
C. to warn people not to use too much gasoline
D. to picture what life will be like if gas runs out
3.What is the best title for this passage?
A. New fuels on the way
B. Cars or bicycles, that is a question
C. End of the good old days
D. From wheels to heels
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