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  3. Imagine fishermen walking down to the seashore, ready to carry out their early morning routine of preparing their boats and net.

Imagine fishermen walking down to the seashore, ready to carry out their early morning routine of preparing their boats and net.

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问题     Imagine fishermen walking down to the seashore, ready to carry out their early morning routine of preparing their boats and net.【C1】______they hope for a good catch of fish. But to their 【C2】______, a horrible sight meets their still sleepy eyes. Thousands of fish have been washed【C3】______dead. The cause of this mass destruction? A red tide!
    Red tides are a global【C4】______. They have been observed on both the Atlantic and the Pacific coasts of the United States and Canada. They have also【C5】______in many other places. Though relatively few people are【C6】______them, red tides are not new.
    In the Philippines, a red tide was first seen in the province of Bataan in 1908. Since then, red tides have been seen in many other【C7】______. A Philippines red tide expert told us that "【C8】______the fish kills, the Philippines has documented 1, 926 cases of dead shellfish poisoning caused by red tides. "
    The term "red tide"【C9】______the discoloration of water that sometimes occurs in certain areas of the ocean or sea. Although the color is often red, it may also be【C10】______of brown or yellow. The World Book Encyclopedia reports that "the discolored areas may range from【C11】______a few square yards to more than 2,600 square kilometers. "
    What causes such discoloration? Red tides are generally caused by several【C12】______of single-celled organisms. These tiny organisms have hair-like projections which they use to【C13】______themselves in water. There are about 2,000 varieties of these organisms, 30 of which carry poisonous【C14】______. These minute organisms usually stay in warm waters with high content of salt.
    A red tide occurs when there is a sudden and rapid【C15】______of these organisms. The concentration of these organisms may【C16】______to 50,000,000 per quart of water! Although scientists do not fully understand why this happens, it is known that these organisms【C17】______when certain conditions simultaneously affect the water. These include abnormal weather, 【C18】______temperatures, an oversupply of nutrients in the water, a generous【C19】______sunlight, and favorable water currents. When a heavy rainfall occurs, minerals and other nutrients are sometimes washed【C20】______the land into coastal water. These nutrients can contribute to the breeding of the organisms. The result? Red tides!
【C20】
选项 A、over
B、on
C、by
D、from
答案D
解析
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考研英语一

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