[单项选择]Throughout most of their lives,human beings perpetually learn and increase their mental capacities.
A. actually
B. readily
C. finally
D. constantly

[单项选择]Throughout most of their lives,human beings perpetually learn and increase their mental capacities.
A. actually
B. readily
C. finally
D. constantly

[单项选择]Throughout most of their lives. human beings perpetually learn and increase their mental capacities.


A. actually
B. readily
C. finally
D. constantly

[单项选择]

Most people think of zoos as safe places for animals, where struggles such as difficulty finding food and avoiding predators don’t exist. Without such problems, animals in zoos should live to a ripe old age.
But matter may not be true for the largest land animals on Earth. Scientists have known that elephants in zoos often suffer from poor health. They develop diseases, joint problems and behavior changes. Sometimes, they even become infertile or unable to have babies.
To learn more about how captivity affects elephants, a team of international scientists compared the life spans of female elephants born in zoos with female elephants living outdoors in their native lands. Zoos keep detailed records of all the animals in their care, documenting factors such as birth dates, illnesses, weight and death. These records made it possible for the researchers to analyze 40 years of
A. have difficulty eating food
B. live to a ripe old age
C. are not afraid of predator
D. develop health problems

[单项选择]第一篇 Longer Lives for Wild Elephants Most people think of zoos as safe places for animals, where straggles such as difficulty finding food and avoiding predators don’t exist. Without such problems, animals in zoos should live to a ripe old age. But that may not be true for the largest land animals on Earth. Scientists have known that elephants in zoos often suffer from poor health. They develop diseases. joint problems and behavior changes. Sometimes, they even become infertile, or unable to have babies. To learn more about how captivity affects elephants, a team of international scientists compared the life spans of female elephants born in zoos with female elephants living outdoors in their native lands. Zoos keep detailed records of all the animals in their care, documenting factors such as birth dates, illnesses, weight and death. These records made it possible for the researchers to analyze 40 years of data on 800 African and Asian elephants in zoos across Europe. The scientists
A. develop poor health.
B. live a long life.
C. give birth to many babies.
D. have difficulty getting food.

[单项选择]The most important character exclusive to human beings is______.


A. humor
B. courage
C. determination
D. initiative

[单项选择]

Most forest fires are caused by human carelessness or ignorance. Forest fire prevention, therefore, is mainly a problem of creating better understanding of the importance of forests, an awareness of the danger of fire in the woods, and a sense of personal responsibility to safeguard the forests from danger. This is not an easy job.
Careless smokers are responsible for thousands of forest fires each year. Many of these are started when cigarette butts(烟蒂 )and matches are thrown from automobiles. Others are caused by hunter, hikers(徒步旅行 ), fishermen, or woods workers who are careless in disposing of their smoking materials. The Forest Service has posted rules in many of the National Forest that prohibit smoking except in certain designated (指定的) areas. Many of the states have laws against throwing lighted materials from automobiles. The prevention of smoker-caused fires, however, depends upon changing the attitudes and behavior of millions of people who smoke in haz
A. holding the fire damages to a minimum
B. people who have changed their attitude and behavior
C. enough rue fighters with good fire-fighting devices
D. carrying out experiments in "seeding" thunder clouds