第三部分:阅读理解(共15小题,每小题2分,满分30分).

阅读下列短文,从每题所给的四个选项(A、B、C和D)中,选出最佳选项。

IN a surprising discovery about where higher life can survive, scientists have found a shrimp-like creature and a jellyfish (水母) swimming beneath an Antarctic ice sheet.

    About 180 meters below the ice where no light can get through, scientists had figured nothing much more than a few microbes (微生物) could exist.

    That’s why a NASA team was surprised when they lowered a video camera to get the first long look at the underbelly (下腹部) of an ice sheet in Antarctica. A curious shrimp-like creature came swimming by and then parked itself on the camera’s cable. Scientists also pulled up a tentacle (触须) they believe came from a jellyfish.

    “We were operating on the presumption (假定) that nothing’s there,” said NASA ice scientist Robert Bindschadler. “It was a shrimp you’d enjoy having on your plate.”

    “We were just gaga (狂热的) over it,” he said of the 7.5cm long, orange creature starring in their two-minute video. Technically, it’s not a shrimp. It’s a Lyssianasid amphipod (片脚类动物), which is distantly related to the shrimp.

    The video is likely to inspire experts to rethink what they know about life in harsh (苛刻的) environments. And it has scientists thinking that if shrimp-like creatures can live below 180 meters of Antarctic ice in freezing dark water, what about other cold places? What about Europa, a frozen moon of Jupiter?

    Cynan Ellis-Evans, a scientist of the British Antarctic Survey called the finding intriguing (吸引人的). He said it was possible the creatures swam in from far away and don’t live there permanently.

    But Kim, who is a co-author of the study, doubts it. The site in West Antarctica is at least 19 km from open seas. Bindschadler drilled a 20cm-wide hole and was looking at a tiny amount of water. That means it’s unlikely that two creatures swam from great distances and were captured randomly in that small of an area, she said.

    Yet scientists were puzzled at what the food source would be for these creatures. While some microbes can make their own food out of chemicals in the ocean, complex life like the shrimp can’t, Kim said.

    So how do they survive? That’s the key question, Kim said.

    “It’s pretty amazing when you find a huge puzzle like that on a planet where we thought we know everything,” Kim said.

56. Scientists had believed that harsh environments could only have been populated by ______.

   A. jellyfish      B. mammal    C. microbes      D. shrimp-like creature

57. According to Kim, the shrimp-like creature ______.

   A. swam great distances to Antarctic                 B. has always lived in the region

   C. gradually evolved from shrimp                   D. has nothing in common with shrimp

58. The finding is significant in that ______.

   A. it marks NASA’s first Antarctic biological study

   B. it proves there is marine life in the Antarctic

   C. it could inspire further study of life in harsh environment

   D. it shows that Lyssianasid amphipod is closely related to shrimp

59. The last three paragraphs suggest that ______.

   A. researchers will look at the places the creatures came from

   B. ice scientists will drill deeper to find more creature

   C. scientists know very little about the planet they live on

   D. further research will be done about what the creatures live on

Scientists are working to develop crop plants that can reduce the amount of water used for agriculture. Almost sixty percent of the world’s freshwater withdrawals from rivers, lakes and other water resources go toward irrigating fields.

Scientists are using biotechnology as well as traditional breeding methods to develop water-saving crops to feed a growing world.

Thomas “Tommy” Carter is a plant scientist in North Carolina. He works for the Agricultural Research Service in the United States Department of Agriculture. He leads Team Drought, a group of researchers at five universities. They have been using conventional breeding methods to develop and test soybeans that can grow well under dry conditions.

Tommy Carter started working on drought-resistant soybeans in 1981. His research has taken him as far as China, where soybeans have been grown for thousands of years.

Farmers in the United States, however, have grown soybeans for only about a century. Tommy Carter says the soybeans they grow are for the most part genetically similar. More differences could better protect crops against climate changes that can reduce production. Those changes include water shortages which could increase from global warming.

The Agriculture Department has a soybean germplasm(胚质) collection, a collection of genetic material passed from one generation to the next. Members of Team Drought studied more than 2,500 examples from the collection.

They looked at ones from the home of soybeans, Asia. They searched for germplasms that could keep plants from weakening and wilting (凋谢)during hot, dry summers in the United States.

Tommy Carter says they found only five. But these slow-wilting lines, he says, produce four to eight bushels(英斗)more than normal soybeans under drought conditions. The yield depends on location and environment.

Scientists are also working on other plants that either use less water or use it better, or both. For example, companies like Monsanto, DuPont and Syngenta have been developing corn with reduced water needs. Monsanto expects to be ready in a few years to market its first corn seeds genetically engineered to resist drought.

68. According to the passage, scientists try to find out how to _______.

A. grow crops with less water

B. increase crop production

C. feed a growing world

D. save the world’s water resource

69. Why did Tommy Carter come to China?

   A. He likes traveling.

   B. China has a long history.

   C. He’s doing research into soybeans.

   D. He works for the Agricultural Research Service.

70. What’s inferred from the passage?

   A. Climate changes lead to global warming.

   B. Water shortages contribute to global warming.

   C. Genetically different soybeans need much water to grow.

   D. Genetically different soybeans help to fight against damaging climate changes.

71. What do we know about slow-wilting plants talked about in the passage?

   A. They yield big profits.

   B. They can grow in almost any climate.

   C. They seem to be drought-resistant.

   D. They need much water for their growth.

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