【答案解析】[听力原文]
Our Concern
Only in the present century has one species of man acquired significant power to alter the nature of his world. The rapidity of change follows the pace of man rather than the pace of nature.
Radiation is now the unnatural creation of man"s tampering with the atom. The chemicals are the creations of man"s inventive mind, having no counterparts in nature. We have put poisonous and biologically potent chemicals into the hands of persons largely ignorant of their potentials for harm.
Future generations are unlikely to forgive our lack of concern.

【答案解析】[听力原文]
Gardening in America
Believe or not, 43,000,000 Americans are gardening. That is about one in six. Not surprisingly, most of them are people who live in the suburbs, and enjoy planting flowers, or maybe a small vegetable garden.
The average age of gardeners in America is about 45 years old; they usually fall somewhere in the middle class. But the fastest growing groups are city dwellers. Many go to large public gardens, as a place designed by the city for garden, and you can actually ranch your own plot.
Still other people use their balconies or roof tops, wherever they can find the space to plant small patches of green.

【答案解析】[听力原文]
The Influence of Life
In the early times when human beings hunted and gathered food, they could only interact with their surroundings as the other lower animals did.
When they learned to make fire, however, they became capable of altering their environment. To provide themselves with fuel, they cut down trees. They also burned clearings in forests to increase the growth of grass and to provide a greater grazing area for the wild animals that human beings fed upon. This development led to farming and the domestication of animals. Only when the process of meeting the basic need for food reached a certain level was it possible for humans to follow other pursuits such as setting up families, forming societies and founding cities.

【答案解析】[听力原文]
Automobiles
It is impossible to say that any one man invented the automobile. Many of the discoveries that went into the creation of the automobile were small in themselves. But together they were important.
"Carriage is running at a speed of 8 to 9 miles an hour." According to automobile historians, this was the first practical use of mechanical power to move a vehicle. After its first run, the machine reportedly burned up while the inventor and his friends were celebrating its success at a pub.
Henry Ford is considered the father of modern automobile mass production. His efforts made it accessible to ordinary people.