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, mor
Thousands of years ago man used handy rocks for his surgical operations. Later he used sharp bone or horn, metal knives and, mor
admin
2013-01-29
42
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 have shown researchers that different energy sources produce beams that have a particular effect on certain living cells. It is possible for eye surgeons to operate on the back of the human eye without harming the front of the eye, simply by passing a laser beam right through the eyeball. No knives, no stitches, no unwanted damage--a true surgical wonder.
Operations which once left patients exhausted and in need of long periods 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 more effective. Altogether, tomorrow may see more and more information coming to light on the diseases which can be treated medically.
Surgeons can now carry out operations which ______.
选项
A、can be performed successfully only on the human eye
B、result in long periods of recovery time for patients
C、result in very little damage to the patients
D、are made much more complicated by using the laser beam
答案
C
解析
转载请注明原文地址:https://kaotiyun.com/show/WY1O777K
0
考博英语
相关试题推荐
Manytheoriesconcerningthecausesofjuveniledelinquency(crimescommittedbyyoungpeople)focuseitherontheindividualor
Amajorreasonforconflictintheanimalworldisterritory.Themaleanimalestablishesanarea.Thesizeoftheareaissuffi
Ifanewcharteroftherightsofpeople(intheFirstWorld,orNorth,orwhateveryouliketocallthepartwherepeopledonoto
AndresearcherssaythatlikethoseliteraryromanticsRomeoandJuliet,theymaybeblindtotheconsequencesoftheirquestsf
To______Americandollarsintoforeigncurrency,multiplytheamountbytherateofexchange.
【T1】Whenwetalkaboutthedangerofromanticlove,wedon’tmeandangerintheobviousheartbreakway--thecheapbetrayals,t
Themostexcitingkindofeducationisalsothemost.Nothingcan【C1】______thejoyofdiscoveringforyourselfsomethingthatis
FrancoisJacobwrotethat"anageorcultureischaracterizedlessbytheextentofitsknowledgethanbythenatureoftheques
U.S.airlinescouldslash70,000morejobsiftherewerewarwithIraqandtheU.S.governmentdidnotgivetheindustry,moreh
Thechild’sbadbehaviorisoftenmorethanawayoftryingto______hismother’sattentionawayfromhissister.
随机试题
下列句子中,有动词使动用法的是()。
毛泽东思想与中国优秀传统文化的精华的关系是【】
驱蛔用治疗姜片虫用
竣工验收遗留问题,由()责成有关单位妥善处理。
对建筑的疏散楼梯进行工程验收时,下列关于疏散楼梯间检查的做法中,正确的有()。
以下属于客户评级的专家判断法的是(’)。
甲企业为增值税一般纳税人,适用的增值税税率为16%,该企业生产主要耗用一种原材料,该材料按计划成本进行日常核算,计划单位成本为每千克20元,2018年6月初,该企业“银行存款”科目余额为300000元,“原材料”和“材料成本差异”科目的借方余额分别为300
《国家“十二五”时期文化改革发展规划纲要》提出的重要方针包括()。
1.请将下列数据建成一个电子表格(存放在A1:E6的区域内),并按照年龄从大到小排序,将个人所得税保留小数点后面两位,在E7单元格中计算5个人个人所得税的总和。姓名性别年龄籍贯个人所得税(元)王廷男
Thetotal______fromlastmonth’scharitydancewerefarmorethanexpected.
最新回复
(
0
)