首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Thousands of years ago man used handy rocks for his surgical operations. Later he used sharp bone or horn, metal knives and more
Thousands of years ago man used handy rocks for his surgical operations. Later he used sharp bone or horn, metal knives and more
admin
2015-06-23
22
问题
Thousands of years ago man used handy rocks for his surgical operations. Later he used sharp bone or horn, metal knives and more recently, rubber and plastic and that was where we stuck, in surgical instrument terms, for many years. 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, in time, 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, for a very large number of different complaints. The word "laser" means: light amplification by stimulated emission of radiation. As we all know, light is hot, any source of light — from the sun itself down to a humble match burning — 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. No knives, no stitches, no unwanted damage — a true surgical wonder. Operations which once left patients exhausted and in need of long period of recovery time now leave them feeling relaxed and comfortable. So much more difficult operations can now be tried.
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. Altogether, tomorrow may see more and more information coming to light on the diseases which can be treated medically.
The author cites the example of eye surgeons to illustrate that______.
选项
A、pinpoint beams have an extensive energy source
B、pinpoint beams with different sources have different effects
C、pinpoint beams have effects on living cells
D、pinpoint beams enable surgeons to do the most different operation
答案
B
解析
细节题。第三段第一句提到,实验证明,来源不同的激光只会对某些特定的活细胞产生作用,即激光来源不同,作用也不同。文章接着就举出了眼科医生治疗眼睛的例子。故答案为B。
转载请注明原文地址:https://kaotiyun.com/show/3Rl7777K
0
大学英语四级
相关试题推荐
Americanuniversitiesarerushingtowardsawirelessfuture.Theyareinstallingnetworksthatletstudentsandteacherssurfth
Americanuniversitiesarerushingtowardsawirelessfuture.Theyareinstallingnetworksthatletstudentsandteacherssurfth
A、Morethan12%.B、Almost50%.C、Nearly60%.D、About70%.B本题涉及数字。本题的听音重点是现在和两年前各自对应的百分比:现在为59%,比两年前上涨了12%,所以两年前应为59%-12%,即47%,故
A、He’llprobablytalkaboutChapter16inclasstoday.B、He’llprobablypostponethetestuntilhetalksaboutChapter16.C、He
ANewYorkTimes-CBSNewspollfoundthatalmost90percentofAmericansthinkthathomeownershipisanimportantpartoftheAm
A、Rise.B、Fall.C、V-shape.D、Zigzag.B对话中男士提到Thedivorcerate...probablywillbegintodropinthenextyearortwo,B)中的fall与drop对
Ifyouareayoungcollegestudent,mostofyourconcernsaboutyourhealthandhappinessinlifeareprobably【B1】______onthe
Thethousandsofpeopleforcedtoabandontheirhomesinrecentweekstofloodwatersarevictimsnotjustofnaturebutofhuman
随机试题
县卫生局以经营发霉变质食品为由对蒋某处以罚款3000元,蒋某不服,申请复议。复议机关做出复议决定后,蒋某仍不服,又向人民法院起诉。诉讼期间被告拒不举证,也不出庭应诉。至一审法院审结前,被告始终未能提供做出具体行政行为所依据的规范性文件和事实证据。一审法院遂
患者女,20岁。发热,厌食厌油一周,查体:皮肤巩膜轻度黄染,肝右下肋未扪及,实验室检查:ALT:178U/L,血清胆红素54μmol/L,尿胆红素阳性,抗HAVIgM(+),抗HBsAg(+),抗HBc(+),抗HCV(-),既往体健,无手术史和输血史。
患者,女,80岁。肿瘤晚期,全身极度衰竭,意识有时模糊。为安慰患者,护士与其交流时应使用的距离是
A.天冬氨酸氨基转移酶B.淀粉酶C.碱性磷酸酶D.谷胱甘肽过氧化物酶E.单胺氧化酶与微量元素硒关系最密切的是
患儿,女,3岁。自幼发现心脏杂音,经常患肺炎,查体胸骨左缘第3~4肋间Ⅳ级粗糙收缩期杂音,心电图示左心室及右心室均肥大,X线片示肺血多。如果患儿服用强心苷时,正确的护理是
乔青服装公司与七郎漂染厂之间因合同发生纠纷,向石厚市仲裁委员会申请仲裁,石厚市仲裁委员会组成仲裁庭审理此案。那么根据我国《仲裁法》的规定,下列有关仲裁裁决的说法,哪些是错误的?
下列哪一选项的表述不能成立?
解放战争时期,毛泽东同志说:“蒋介石两个拳头(指陕北和山东)这么一伸,他的胸膛露出:来了。所以,我们的战略就是要把这两个拳头紧紧拖住,对准他的胸膛插上一刀。”这里说的“插上一刀”指的是()。
食物链是各种生物通过一系列吃与被吃的关系彼此联系起来的序列。“螳螂捕蝉,黄雀在后”这句谚语生动地体现了食物链的原理。下列与该食物链有关的说法中正确的是()。
有人认为:“在婚姻关系存续期间,夫或妻以个人名义所负的债务是夫或妻的个人债务。”请对该说法加以辨析。
最新回复
(
0
)