问题
单项选择题 A1/A2型题
调节彩色血流显像内容，错误的是（）
A.调节彩色增益
B.调节彩色滤波器
C.调节彩色速度标尺
D.调节脉冲多普勒的取样容积
E.调节彩色取样框大小
答案
参考答案：D
解析：调节彩色血流显像包括：调节彩色增益、彩色滤波器、彩色速度标尺、彩色取样框大小。而脉冲多普勒是以频谱的方式显示某点的血流速度、方向和性质。
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调节彩色血流显像内容，错误的是（）
A.调节彩色增益
B.调节彩色滤波器
C.调节彩色速度标尺
D.调节脉冲多普勒的取样容积
E.调节彩色取样框大小
参考答案：D
解析：调节彩色血流显像包括：调节彩色增益、彩色滤波器、彩色速度标尺、彩色取样框大小。而脉冲多普勒是以频谱的方式显示某点的血流速度、方向和性质。
| 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. |
It can be deduced from this passage that one should______.
A．learn new skills
B．be open-minded
C．have a good personality
D．keep pace with the times