[单项选择]Questions 27～30A. The man has always been a valuable employee.
B. The man has often been late for work after lunch.
C. The man has been addicted to alcohol while running errands.
D. The man has been engaging in work-related activities.

[单项选择]Man has （）been to the Moon
A. last  
B. already 
C. ago  
D. in

[单项选择]Being a man has always been dangerous. There are about 105 males born for every 100 females, but this ratio drops to near balance at the age of maturity, and among 70-year-olds there are twice as many women as men. But the great universal of male mortality is being changed. Now boy babies survive almost as well as girls do. This means that, for the first time, there will be an excess of boys in those crucial years when they are searching for a mate. More important, another chance for natural selection has been removed. Fifty years ago, the chance of a baby (particularly a boy baby) surviving depended on its weight. A kilogram too light or too heavy meant almost certain death. Today it makes almost no difference. Since much of the variation is due to genes, one more agent of evolution has gone.
There is another way to commit evolutionary suicide: stay alive, but have fewer children. Few people are as fertile as in the past. Except in some religious communities, very few women ha
A. Wealth people tend to have fewer children than poor people.
B. The upper class population is 80% smaller than that of the tribes.
C. Natural selection hardly works among the rich and the poor.
D. India is one of the countries with a very high birth rate.

[填空题]The rate at which man has been storing up useful knowledge about himself and the universe has been spiraling upward for 10,000 years. The rate t (66) a sharp upward leap thousands of years ago, w (67) the invention of writing, but even so it remained painfully slow o (68) centuries of time. In knowledge- (69) (acquire) the next great leap forward did not occur until the invention of movable type in the fifteenth century by Gutenberg and others. Prior (70) 1500, by the most optimistic est (71) , Europe was producing books at a rate of 1, 000 titles per year. This means that it would take a full century to produce a library of 100,000 titles. The rate had ac (72) so sharply by 1950, four and a half centuries later, (73) Europe was producing 120,000 titles a year. (74) once took a century now took only ten months. By 1960, a s (75) decade later, the rate had made another significant jum