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  3. Thousands of years ago man used handy rocks for his surgical operations. Later he used sharp bones or horns, metal knives and mo

Thousands of years ago man used handy rocks for his surgical operations. Later he used sharp bones or horns, metal knives and mo

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问题     Thousands of years ago man used handy rocks for his surgical operations. Later he used sharp bones or horns, metal knives and more recently, rubber and plastic. In the 1960s a new tool was developed, one which was, first of all, to be of great practical use to the armed forces and industry, but which was also to revolutionize the art and science of surgery.
    The tool is the laser and it is being used by more and more surgeons all over the world. As we all know, light is hot, and any source of light will give warmth. But light is usually spread out over a wide area. The light in a laser beam, however, is concentrated. This means that a light with no more power than that produced by an ordinary electric light bulb becomes intensely strong as it is concentrated to a pinpoint-sized beam.
    Experiments with these pinpoint beams showed researchers that different energy sources produce beams that have a particular effect on certain living cells. It is now possible for eye surgeons to operate on the back of human eye without harming the front of the eye, simply by passing a laser beam right through the eye-ball. Operations which once left patients exhausted and in need of long period of recovery time now leave them feeling relaxed and comfortable.
    The rapid development of laser techniques in the past ten years has made it clear that the future is likely to be very exciting. Perhaps some cancers will be treated with laser in a way that makes surgery not only safer but also more effective.
After the use of the laser beam, surgeons can perform operations which ______ .
选项 A、leave their patients with negative effects
B、can treat only human eye diseases
C、do little damage to their patients
D、make their patients need a long time to recover
答案C
解析 事实细节题。题干的意思是“使用激光束做手术时医生可以…”。文中第三段提到“曾经一度让患者疲惫不堪，并且术后恢复时间漫长的手术现在让患者变得很轻松很舒服”，可以排除A和D。由文中最后一句“也许一些癌症也能够用激光来治疗”可知B选项不正确。C选项意思为“使患者受到很小的伤害”。所以正确答案为C。
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