[C] Too many people on earth and a few rapid increase in the number added each year.

　　[D] A long period when death rates exceed birthrates and then a short period with higher

　　fertility and lower mortality.

　　59. During the first period of demographic history, societies were often in danger of extinction because ________.

　　[A] only one in ten persons could live past 40

　　[B] there was higher mortality than fertility in most places

　　[C] it was too dangerous to have babies due to the poor conditions

　　[D] our ancestors had little enthusiasm for more children

　　60. Which statement is TRUE about population increase?

　　[A] There might be an increase of 2.2 billion persons from 1975 to the year 2000.

　　[B] About 50,000 babies are born annually at present.

　　[C] Between 8000 B.C. and the present, the population increase is about 80,000,000 persons　each year.

　　[D] The population increased faster between 8000 B.C. and 1650 than between 1650 and the　present.

　　61. The author of the passage intends to ________.

　　[A] warn people against the population explosion in the near future

　　[B] compare the demographic growth pattern in the past with that after 1650

　　[C] find out the cause for rapid increase in population in recent years

　　[D] present us a clear and complete picture of the demographic growth