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The population problem may
be the 51 one of the world today. The world’s population is growing 52 . Two thousand years ago, there were only 250 million people 53 the earth. Four hundred years ago, the number
was 54 500 million. But at the beginning of the 55 century, the world’s population was about 1,700
million. In 1970,
this number was 3,600 million. In 1990, the number was five billion. A 56 report says that the world
population will 57 six billion by the end of the 20th
century. This is just
ten 58 after it 59 five billion. People say that by the year
2010, 60 may be seven billion.
51.A.great B.greater C.greatest D.greating
52.A.faster and
faster B.fast and fast
C.fastest and fastest D.faster and fast
53.A.in B.on C.at D.for
54.A.nearly B.more C.almost D.over
55.A.twenty B.twelve C.twentieth D.twelfth
56.A.USA B.UN C.PRC D.PLA
57.A.past B.pass C.passed D.passes
58.A.weeks B.months C.seasons D.years
59.A.get B.gets C.reached D.reach
60.A.this B.its C.one D.it