中考英语完形填空训练（001） The population problem may be the 1 one of the world today The worlds population is growing 2 Two thousand years ago, there were only 250 million people 3 the earth Four hundred years ago, the number was 4 500 million But at the beginning of the 5 century, the worlds population was about 1,700 millionIn 1970, this number was 3,600 million In 1990, the number was five billion A 6 report says that the world population will 7 six billion by the end of the 20th
