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
2015-02-09
49
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.
Which of the following is NOT a tool used for surgical operations before the 1960s?
选项
A、Bone.
B、Metal knives.
C、Scissors.
D、Rubber and plastic.
答案
C
解析
转载请注明原文地址:https://kaotiyun.com/show/8Zq7777K
0
大学英语四级
相关试题推荐
Academicqualifications’valueintheworkplaceisabigissueforstudents,policymakersandtaxpayers,especiallyastherisin
A、Shelivesonherown.B、Shehasnochildrenorgrandchildren.C、Shelivesinanursinghome.D、Herchildrenvisithereveryot
HappinessandSadnessA)Happinessandsadnessaretwomostbasicandfamiliarfeelingsforhumanbeings.Recently,peoplehavea
HappinessandSadnessA)Happinessandsadnessaretwomostbasicandfamiliarfeelingsforhumanbeings.Recently,peoplehavea
HappinessandSadnessA)Happinessandsadnessaretwomostbasicandfamiliarfeelingsforhumanbeings.Recently,peoplehavea
A、Becausethedemandforfoodincreased.B、Becausebadweathercausedthethreatoffoodshortage.C、Becausetheproductionoff
Oneofthemostcontentious(有争议的)issuesinthevastliteratureaboutalcoholconsumptionhasbeentheconsistentfindingthatth
"MadeinChina"lostitsnovelty(新颖)longago.Thelabelhasbecome【C1】______inmuchoftheworld,sticktoshoes,toys,clothes
A、Attheairport.B、Inarestaurant.C、Inabookingoffice.D、Atthehotelreception.D女士说她没有找到男士的预订记录,男士解释说秘书称已经给他订好了房间,他在早上上飞机
A、Hehastoworkwithhisbrother.B、Hehasnodefiniteplans.C、Heusuallyworksonweekends.D、Hisplansdependonthewoman.
随机试题
A.入院后即开始B.术前3天开始C.手术前1天D.手术前12小时开始E.手术前2小时开始
试述行政组织的变革趋势。
听泉东山魁夷鸟儿飞过旷野。一批又一批,成群的鸟儿接连不断地飞了过去。有时候四五只联翩飞翔,有时候排成一字长蛇阵。看,多么壮阔的鸟群啊!……鸟儿呜叫着,它们和睦相处,互相激励;有时又彼此憎恶,格斗、伤残。有的鸟儿因疾病、疲惫
10岁男孩因发热咳嗽5天,伴胸闷气促,既往无先心病史。查体:体温38.5℃,气促,口周轻度发绀,精神萎靡,呼吸30次/分,两肺呼吸音粗,少量中湿啰音,心率160次/分,ST明显低钝,肝脏肋下3cm。X线检查和心电图示左右心室扩大,WBC7.0×109/
哪些情况下可以提起公益诉讼?()
按信息资源的属性划分,工程管理信息资源包括()。
下列属于基本存款账户存款人的有()。
根据宪法和法律的规定,我国的国家机关主要由()组成。
设随机变量Xi~(i=1,2),且满足P(X1X2=0)=1,则P(X1=X2)等于().
在考生文件夹下,打开文档word.docx,按照要求完成下列操作并以该文件名(word.docx)保存文档。【文档开始】国书与谎话美国首任总统乔治.华盛顿家里有许多国书,国书中还夹杂一些杂树,为让国书生长茂盛,应该将杂树除掉。一天,华盛顿给
最新回复
(
0
)