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| 文章出处：学生大考试站 发布时间：2005-10-12 |
ine biologists realized that if new measures were not taken, oysters would become extinct or at best a luxury food. So they set up well equipped hatcheries and went to work. But they did not have the proper equipment or the skill to handle the eggs. They did not know when, what, and how to feed the larvae. And they knew little about the predators t hat attacked and ate baby oysters by the millions. They failed, but they doggedly kept at it. Finally, in the 1940’s a significant breakthrough was made.
The marine biologists discovered that by raising the temperature of the water, t hey could induce oysters to spawn not only in the summer but also in the fall, winter, and spring. Later they developed a technique for feeding the larva e and rearing them to spat. Going still further, they succeeded in breeding new s trains that were resistant to diseases, grew faster and larger, and flourished in water of different salinities and temperatures. In addition, the cultivated oysters tasted better!
31. Which of the following would be the best title for the passage?
A The Threatened Extinction of Marine Life
B The Cultivation of Oysters
C The Discoveries Made by Marine Biologists
D The Varieties of Wild Oysters
32. In the passage, which of the following is NOT mentioned as a stage of a n&nbs
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