American beekeeping operations have been hit hard by what scientists call colony collapse disorder. Almost half of their worker bees have disappeared during the past season. C.C.D. has also been reported in Israel, Europe and South America. Bees fly away from the hive and never return. Sometimes they are found dead; other times they are never found. Many crops and trees depend on pollination (授粉) by bees to help them grow.

A new report says virus may be at least partly responsible for the disorder in honey bee colonies in the United States. This virus is called Israeli acute paralysis virus. It was first identified in Israel in 2004. Ian Lipkin at Columbia University in New York and a team reported the new findings in Science magazine. Doctor Lipkin says the virus may not be the only cause. He says it may work with other causes to produce the collapse disorder.

The team found the virus in colonies with the help of a map of honey bee genes that was published last year. They examined thirty colonies affected by the disorder. They found evidence of the virus in twenty five of them, and in one healthy colony. The next step is further testing of healthy hives.

The researchers suggested that the United States may have imported the disorder in bees from Australia. They say the bees may carry the virus but not be affected.

The idea is that unlike many American bees, the ability of Australian bees to fight disease has not been hurt by the varroa mite. This insect attacks honey bees, which could make the disorder more likely to affect a hive. Australian bee producers reject these suspicions.

And some researchers suspect that bee production in the United States is down mainly because of the weather. Honey bees gather nectar(花蜜) from flowers and trees. The sweet liquid gives them food and material to make honey. But cold weather this spring in the Midwest reduced the flow of nectar in many flowers. Many bees may have starved. Dry weather in areas of the country could also be playing a part.

Wayne Esaias is a NASA space agency scientist who keeps bees in his free time. He lives in central Maryland, where he has found that flowers are blooming a month earlier than they did in 1970, which may be partly responsible for the disorder. Wayne Esaias is organizing a group of beekeepers to document nectar flow around the country.

 

57. The researchers found the virus         .

       A. with the help of C.C.D.

       B. by researching the causes of bee death

       C. with the help of a map of honey bee genes

       D. with the help of a scientist of NASA Space Agency

58. What is the passage mainly about?

       A. American beekeeping industry has been strongly influenced by the bee disorder.

       B. Studies are being carried out on the causes of the bee disorder, but questions remain.

       C. How the causes of the bee disorder in U.S have been found.

       D. The bee production in U.S is down.

59. How many possibilities may be involved in the bee disorder according to the passage?

       A. Three                   B. Four                     C. Five                     D. Six

60. We can infer that         from the passage.

       A. Israeli acute paralysis virus should be responsible for the disorder.

       B. The solution to the disorder will be found eventually.

       C. American bees are more likely to defend themselves against hurt from other insects than Australian ones.

       D. The crop and plant production in U.S may be influenced by the bee disorder.

Here are some of the world’s most impressive subways

The Tokyo Metro and Toei Lines

Features: The Tokyo Metro and Toei lines that compose Tokyo’s massive subway system carry almost 8 million people each day, making it the busiest system in the world. The system is famous for its oshiya--- literally, “pusher”--- who shove passengers into crowded subway cars so the doors can close. And you think your commute is hell.    

The Moscow Metro

 

Features: The Moscow Metro has some of the most beautiful stations in the world. The best of them were built during the Stalinist era and feature chandeliers(枝形吊灯), marble moldings and elaborate murals(精美的壁画). With more than 7 million riders a day, keeping all that marble clean has got to be a burden.

 

The Hong Kong MTR

 

Features: The Hong Kong MTR has the distinction of being one of the few subway systems in the world that actually turns a profit. It’s privately owned and uses real estate development along its tracks to increase income and ridership. It also introduced “Octopus cards” that allow people to not only pay their fares electronically, but buy stuff at convenience stores, supermarkets, restaurants and even parking meters. It’s estimated that 95 % of all adults in Hong Kong own an Octopus card .

Shanghai Metro

 

Features: Shanghai is the third city in China to build a metro system, and it has become the country’s largest in the 12 years since it opened. Shanghai Metro has 142 miles of track and plans to add another 180 miles within five years. By that point, it would be three times larger than Chicago “L”. The system carries about 2.18 million people a day.

 

The London

Metro

Features: Londoners call their subway the Underground, Even though 55 percent of it lies above ground. No matter. When you’ve got the oldest mass-transit system in the world, you can call it anything you like. Trains started in1863 and they’ve been running ever since. Some 3 million people ride each day, every one of them remembering to “Mind the gap”.

 

45. Which one can provide the riders some wonderful decorations at the stations?

       A. The Tokyo Metro and Toei Lines               B. The Moscow Metro

C. The London Metro                                   D. The Hong Kong MTR

46. ________ is done with the purpose of making money.                 

A. The Tokyo Metro and Toei Lines                 B. The Moscow Metro

C. The London Metro                                     D. The Hong Kong MTR

47. We can learn from the passage that Shanghai Metro ________.

A. carries the most people each day

B. is the world’s largest

C. may be larger than the Chicago “L” in the future

D. is the busiest in the world

48. How many subways carry more than 5 million people per day?

A. 2                         B. 3                  C. 4                 D. 5

      
 0  31758  31766  31772  31776  31782  31784  31788  31794  31796  31802  31808  31812  31814  31818  31824  31826  31832  31836  31838  31842  31844  31848  31850  31852  31853  31854  31856  31857  31858  31860  31862  31866  31868  31872  31874  31878  31884  31886  31892  31896  31898  31902  31908  31914  31916  31922  31926  31928  31934  31938  31944  31952  151629 

违法和不良信息举报电话:027-86699610 举报邮箱:58377363@163.com

精英家教网