Part IV Cloze (15 minutes, 10 points)

　　Directions: In this part, there is a passage with twenty blanks. For each blank there are four choices marked A, B, C and D. Choose the best answer for each blank and mark the corresponding letter on your ANSWER SHEET with a single line through the center.

　　Imagine fishermen walking down to the seashore, ready to carry out their early morning routine of preparing their boats and net. ___71___ they hope for a good catch of fish. But to their ___72___ , a horrible sight meets their still sleepy eyes. Thousands of fish have washed ___73___ dead. The cause of this mass destruction? A red tide!

　　Red tides are a global ___74___. They have been observed on both the Atlantic and the Pacific coasts of the United States and Canada. They have also___75___ in many other places. Though relatively few people are ___76___ 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 ___77___. A Philippines red tide expert told us that " ___78___ the fish kills, the Philippines has documented 1, 926 cases of dead shellfish poisoning caused by red tides. "

　　The term "red tide" ___79___ 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 ___80___ of brown or yellow. The World Book Encyclopedia reports that "the discolored areas may range from ___81___ a few square yards to more than 2, 600 square kilometers. "

　　What causes such discoloration? Red tides are generally caused by several ___82___ of single-celled organisms. These tiny organisms have hair-like projections which they use to ___83___ themselves in water. There are about 2, 000 varieties of these organisms, 30 of which carry poisonous ___84___. These minute organisms usually stay in warm waters with high content of salt.

　　A red tide occurs when there is a sudden and rapid ___85___ of these organisms. The concentration of these organisms may ___86___ to 50, 000, 000 per quart of water! Although scientists do not fully understand why this happens. It is known that these organisms ___87___ when certain conditions simultaneously affect the water. These include abnormal weather, ___88___ temperatures, an oversupply of nutrients in the water, a generous ___89___ sunlight, and favorable water currents. When a heavy rainfall occurs, minerals and other nutrients are sometimes washed ___90___ the land into coastal waters. These nutrients can contribute to the breeding of the organisms. The result? Red tides!

　　71. A. As a result   B. As it is   C. As expected   D. As usual

　　72. A. satisfaction   B. disappointment  C. astonishment   D. regret

　　73. A. ashore    B. aboard   C. aside     D. across

　　74. A. question   B. crisis    C. phenomenon   D. situation

　　75. A. occupied   B. occurred   C. acquired    D. accused

　　76. A. assured of   B. worried about  C. concerned about  D. aware of

　　77. A. sandy beaches  B. river mouths  C. coastal areas   D. reef areas

　　78. A. except    B. besides   C. despite    D. without

　　79. A. applies to   B. sums up   C. copes with    D. leads to

　　80. A. shadows   B. shades   C. shakes    D. shapes

　　81. A, less than   B. more than   C. as much as   D. as little as

　　82. A. components   B. elements   C. ingredients   D. species

　　83. A. propel    B. probe    C. proceed    D. prompt

　　84. A. materials   B. substances   C. masses    D. objects

　　85. A. bolt    B. block    C. bloom    D. blast

　　86. A. scale    B. plunge   C. gauge    D. swell

　　87. A. accelerate   B. accommodate  C. accumulate   D. accompany

　　88. A. optimum   B. minimum   C. maximum    D. momentum

　　89. A. means of   B. amount of   C. way to    D. account for

　　90. A. over    B. on    C. by     D. from

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