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from 23 percent of American beekeeping businesses. Causes of the occurrence, however, have remained a
puzzle.
Now, scientists from several universities and the United States Department of Agriculture say they have a
possible explanation for the bee decline (数量下降). It is a little known virus called Israeli acute-paralysis virus
(IAPV).The virus kills bees. Researchers in Israel first described it in 2004, but until now, bee experts haven't
paid much attention to it.
When trying to find out why the bees were disappearing, a research team at Columbia University studied
bee communities, some with and others without decline. The research turned up large numbers of two types
of fungi (真菌) once believed of causing the bee decline. The research results, however, showed that the
fungi were almost as common in communities without a decline as they were in communities with a decline.
The research concluded that the two fungi probably weren't the cause.
Studies of the presence of IAPV, however, showed more interesting information. In those studies, done
by a team at Pennsylvania State University in University Park, the virus showed up in 83 percent of samples
from communities with symptoms. Only five percent of samples from symptomless communities had it.
Scientists still don't know whether IAPV can single-handedly cause the bee decline. They believe that even
if the virus is making communities sick, it could have a partner in crime. It's possible, for instance, that insects
or chemicals in the environment weaken bees, making them more likely to catch IAPV.
Scientists are still trying to figure out how IAPV came to the United States. The United States now allows
bee products to be imported from Canada, Australia, and New Zealand. If it turns out that this trade is
spreading disease, the rules might eventually change.
B. is spread by a kind of fungi
C. is still not fully understood
D. is caused by the imported bee products
B. comparing
C. examining
D. investigating
B. the virus could also cause other damages
C. the virus is not the only cause for the bee decline
D. the virus may be caused by the polluted environment
B. A Virus-IAPV
C. Fungi and Virus
D. Disappearing Bees
Mrs. Green was eighty,but she had a small car ,and she always drove to the shops in it on Sunday and bought her food.
She did not drive fast,because she was old,but she drove well and never hit anything.Sometimes her grandchildren said to her,“Please don’t drive your car,we can take you to the shops.”
But she always said,“No,I like driving.I've driven for fifty years and I’m not going to stop now.”
Last Sunday she stopped her car at some traffic lights because they were red,and then it did not start again.the lights were green,then yellow,then red,then green again,but her car did not start.
“What am I going to do now?”she said.
But then a policeman came and said to her kindly,“Good morning,Don’t you like any of our colors today?”
判断下更句子的正误，正确的用“T”表示，错误的用“F”表示：
1．She always bought her food on Saturday.
( )
2．She did not drive well.
( )
3．She has driven for fifty years.
( )
4．Her grandchildren were happy when she drove her car.
( )
5．Mrs. Green’s engine did not start that day.
( )
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But, curiously, one of the rarest coins in the world is not made of gold, but of the relatively cheaper silver. In 1840, the United States mint struck 19, 570 silver dollars. That is what its records show. Today only six of this original number remain and these are unlikely ever to the auction market. So what happened to some 19, 564 large silver coins, not the easiest sort of things to lose? One of the more romantic theories is that they were part of the payment to Napoleon for the American territory then known as Louisiana. But they never reached France. Somewhere in the Gulf of Mexico, the ship transporting them was sunk, either by a storm or by pirates. The probable answer to the mystery is that they were melted down—since the silver value was greater than the actual value of the coin. What really happened to the rest will probably always remain a mystery. What .is known is that whoever can come up with one will find himself instantly rich.
1. It can be inferred from the passage that——.
A. money buys as much as it did before
B. money does not buy as much as it did before
C. paper money buys more than metal money
D. metal money buys more than paper money
2. Which of the following is true of a coin?
A. The longer it is held, the less valuable it becomes.
B. The more it wears out, the more valuable it becomes.
C. The less it gets scratched, the less it values.
D. The longer it lasts, the more it values.
3. Coins becomes more valuable because
A. they make purses and pockets untidy
B. the price of metal goes up
C. they fall more readily into a category for collections due to their duration
D. both B and C
4. What really happened to some 19, 564 large silver coins?
A. They were melted down. B. They were sunk in the Gulf of Mexico.
C. It is still mystery. D. They were stolen by pirates.
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