More than a century ago, the relationship between glacial ice and the amount of water in the ocean basins was first seen. When the great ice sheet covered vast land areas, the sea level was lowered because the normal return of water from land to the ocean was reduced. As a result, the sea level rose as Ice Age glaciers melted allowing the melted waters to flow into the ocean. If all the glacial ice on the surface of the earth today should melt, the sea level might rise by more than 150 feet. Shoreline variations are also produced through elevation or depression of the land. During times of glacier formations the great weight of the ice slowly depressed the earth's crust. Removal of the weight through glacier melting allowed the slow return of the crust to its former position. Changes in the Great Ice climates from cool and wet to warm and dry produced climate changes far from the glaciated area. For example, at times of cool-wet glacial climates, levels of inland lakes rose, in contrast to the depression of sea level. During the warm-dry interglacial climates, lake levels were lowered. The ancient lake Bonneville, largest of the glacial lakes in Western United States, once covered more than 20,000 square miles. It had a maximum depth of more than 1,000 feet. Great Salt Lake in Utah is the shrunken remnant of this once large lake.
Although the first time that early man walked on the earth is uncertain, he is largely a product of the Great Ice Age. Present information shows that during this time he evolved rapidly both physically and culturally. His most primitive tools and skeletal remains have been found in some of the oldest deposits contemporary with the Great Ice Age in Africa, Asia and Europe. These are often associated with remains of extinct animals. With the disappearance of the great ice sheets, the Bronze and Iron Age cultures evolved. About this time many animals suited to cooler climates died.
Although much remains to be learned, the story of the Great Ice Age is being unfolded through the efforts of specialists in many fields. Recording field observation, new theories and methods, and worldwide studies of existing glaciers are bringing a clearer understanding of the Great Ice Age.
26. Which of the following is NOT implied in the passage?
A. Man has a lot more to learn about the Great Ice Age.
B. The art of making tools was instrumental in bringing about the evolution of human brain.
C. Many species were not suited to the warmer climates of the Bronze and Iron Age.
D. The relationship between glacial ice and the amount of water in the ocean basins was not seen until more than a hundred years ago.
27. According to the article, which of the following will induce the depression of sea level?
A. formation of great masses of ice sheet on the land
B. precipitation
C. shoreline variations
D. the advent of warm-dry interglacial climates
28. Why does the author cite the example of the Great Salt Lake in Utah?
A. to show that it is a lake created in the Great Ice Age
B. to show that it once was the largest lake in the United States
C. to show that it evolved from the Bronze and Iron Age
D. to show that it is what remained of the once large lake Bonneville
29. Which of the following can be learned about early man based on the information provided in the passage?
A. The exact time of his appearance on the Earth is uncertain.
B. He evolved rapidly physically and culturally during the Bronze and Iron Age.
C. The ability to make primitive tools distinguished man from other animals.
D. Early man lived mainly on animals hunted.
30. The best source of information about the Great Ice Age is obtained from _____.
A. rock formations
B. fossil remains
C. primitive tools used by early man
D. Antarctica's ancient glacier
Questions 31 to 35 are based on the following passage:
Prolonging human life has increased the size of the human population. Many people alive today would have died of childhood diseases if they had been born a hundred years ago. Because more people live longer, there are more people around at any given time. In fact, it is a decrease in death rates, not an increase in birth rates, that has led to the population explosion.
Prolonging human life has also increased the dependency load. In all societies, people who are disabled or too young or too old to work are dependent on the rest of society to provide for them. In hunting and gathering cultures, old people who could not keep up might be left behind to die. In times of famine, infants might be allowed to die because they could not survive if their parents starved, whereas if the parents survived they could have another child. In most contemporary (当代的) societies, people feel a moral obligation to keep people alive whether they can work or not. We have a great many people today who live past the age at which they want to work or are able to work; we also have rules which require people to retire at a certain age. Unless these people were able to save money for their retirement, somebody else must support them. In the United States many retired people live on social security checks which are so little that they must live in near poverty. Older people have more illness than young or middle-aged people; unless they have wealth or private or government insurance, they must often go on welfare if they have a serious illness.
When older people become senile or too weak to care for themselves, they create grave problems for their families. In the past and in some traditional cultures, they would be cared for at home until they died. Today, with most members of a household working or in school, there is often no one at home who can care for a sick or weak person. To meet this need, a great many nursing homes and convalescent (康复的) hospitals have been built. These are often profit-making organizations, although some are sponsored (赞助) by religious and other nonprofit groups. While a few of these institutions are good, most of them are simply dumping grounds for the dying in which care is given by poorly paid, overworked, and under-skilled personnel.
31. What was the cause to the population growth according to the passage?
A. increase of birth rate
B. advance in medical care
C. well-administered social welfare
D. the decrease of death rate
32. It can be learned from the passage that in some traditional societies _____.
A. infants may be left to die when there isn't enough food to go around
B. old and sick people are cared for at home until they died
C. people are required to retire at a certain age
D. people who are too weak or ill have to take care of themselves
33. What does the word “senile” in the first line of the last paragraph mean?
A. advanced in age B. sick
C. disabled D. capricious
34. What is the author's attitude toward the nursing homes and convalescent hospitals mentioned in the paragraph?
A. suspicious B. optimistic C. neutral D. critical