Directions: There are 20 blanks in the following passage, and for each blank there are 4 choices marked A, B, C and D at the end of the passage. Then blacken the corresponding letter on the Answer Sheet.

　　Scientists say that something very serious is happening to the earth. It will begin to get __56__ in the following years. There will be major changes in ___57__ in the new century. Coastal waters will have a __58__ temperature. This will have a __59__ effect on agriculture. In northern areas, the __60__ season will be ten days longer by the year 2010. However, in warmer areas, it will be too dry. The __61__ of water could __62__ by eighty percent. This would __63__ a large decrease in agriculture production.

　　World temperature could __64__ two degrees centigrade by the year 2040. However, the increase could be three times as great in the Artic and Antarctic area. This could cause the __65__ sheets to melt and raise the __66__ of the oceans __67__ one to two meters. Many coastal cities would be __68__ water.

　　Why is this happening? There is too __69__ carbon dioxide in the air. __70__ oil, gas and coal burn, they create large amounts of carbon dioxide. This carbon dioxide lets __71__ enter the earth’s atmosphere and __72__ the earth. However, it doesn’t let as much heat __73__ the atmosphere and enter space. It’s like a blanket. The heat __74__ the sun can pass through the blanket to warm the earth. The heat __75__ there and can’t escape through the blanket again.

　　Scientists call this the green-house effect.

　　56. A warmer B colder C better D worse
　　57. A land B agriculture C climate D weather
　　58. A lower B higher C normal D proper
　　59. A good B general C serious D useful
　　60. A getting B playing C taking D growing
　　61. A much B many C amount D number
　　62. A fall B decrease C refuse D rise
　　63. A lead B keep C make D cause
　　64. A increase B drop C lift D realize
　　65. A water B rain C stone D ice
　　66. A degree B level C coast D area
　　67. A by B to C of D with
　　68. A above B under C below D over
　　69. A little B many C few D much
　　70. A If B Because C When D Why
　　71. A sunlight B air C rain D gas
　　72. A cold B protect C hurt D heat
　　73. A enter B get C leave D reach
　　74. A through B by C from D on
　　75. A stores B arrives C stands D stays