| 不定项选择 |
| 物体沿一条直线运动，下列说法正确的是（ ） |
A．物体在某时刻的速度为3m/s，则物体在一秒内一定走3m B．物体在某一秒内的平均速度是3m/s，则物体在这一秒内的位移一定是3m C．物体在某段时间内的平均速度是3m/s，则物体在一秒内的位移一定是3m D．物体在某段位移内的平均速度是3m/s，则物体在通过这段位移一米时的速度一定是1.5m/s |
答案：B
| Modern industrial society grants little status to old people. In fact, such a society has a system of built-in obsolescence. There is no formal system for continuing our education throughout our life in order to keep up with rapidly changing knowledge. When our education and job skills have grown obsolete, we are treated exactly like those who have never gained an education or job skills and are not encouraged or given the opportunity to begin anew. As a society becomes more highly developed, the overall status of older people diminishes. Improved health technology creates a large pool of old people, who compete for jobs with the young. However, economic technology lowers the demand for workers and creates new jobs for which the skills of the aged are obsolete, forcing older people into retirement. At the same time, young people are being educated in the new technology and are keeping pace with rapid changes in knowledge. Finally, urbanization creates age-segregated neighborhoods. Because the old live on fixed incomes, they must often live in inferior housing. All these factors -- retirement, obsolete knowledge and skills, inferior standards of living -- lower the status of the aged in society. A century ago, when one could expect to live only to 50 or so, the life span more or less coincided with the occupation and family cycle. But today the average life span allows for fifteen to twenty years of life after these cycles. It appears that our life span is outpacing our usefulness in society. |
The author’s attitude toward the aged is______.
A．realistic
B．optimistic
C．pessimistic
D．sympathetic