首页
财务会计
医药卫生
金融经济
考公考编
外语考试
学历提升
职称考试
建筑工程
IT考试
其他
登录
金融经济
Many people believe the glare from snow causes snow-blindness. Yet, dark glas...
Many people believe the glare from snow causes snow-blindness. Yet, dark glas...
admin
2020-12-24
53
问题
Many people believe the glare from snow causes snow-blindness. Yet, dark glasses or not, they find themselves suffering from headaches and watering eyes, and even snow-blindness, when exposed to several hours of "snow light".
The United States Army has now determined that glare from snow does not cause snow- blindness in troops in a snow-covered country. Rather, a man's eyes frequently find nothing to focus on in a broad expanse of barren snow-covered terrain. So his gaze continually shifts and jumps back and forth over the entire landscape in search of something to look at. Finding nothing, hour after hour, the eyes never stop searching and the eyeballs become sore and the eye muscles ache. Nature offsets this irritation by producing more and fluid which covers the eyeball. The fluid
covers the eyeball in increasing quantity until vision blurs,then is observed, and the result is total, even though temporary, snow-blindness.
Experiments led the Army to a simple method of overcoming this problem. Scouts ahead of a main body of troops are trained to shake snow from evergreen bushes, creating a dotted line as they cross completely snow-covered landscape. Even the scouts themselves throw lightweight, dark colored objects ahead on which they too can focus. The men following can then see something. Their gaze is arrested. Their eyes focus on a bush and having found something to see, stop scouring the snow-blanketed landscape. By focusing their attention on one object at a time, the men can cross the snow without becoming hopelessly snow-blind or lost. In this way the problem of crossing a solid white terrain is overcome.
Snow-blindness may be avoided by_________.
选项
A. concentrating to the solid white terrain
B. searching for something to look at in snow-covered terrain
C. providing the eyes with something to focus on
D. covering the eyeballs with fluid
答案
C
解析
根据第二段可知,雪盲症的发生最根本的原因是茫茫雪原上没有除了白色以外的颜色 可以看到.因而眼睛疲劳,因此提供可以聚焦的物体是根本预防办法,故选C。
转载请注明原文地址:https://ti.zuoweng.com/ti/Ixk8KKKQ
相关试题推荐
TherearemuchmanymorepeoplethanIexpected.A.ThereB.muchC.manyD.than
Imetseveralpeoplethere,twoof______beingforeigners.A.whomB.themC.wh
Webelievethat_________recentchangesinstatelaws,themajorityvotestan...
Manypeoplebelievetheglarefromsnowcausessnow-blindness.Yet,darkglas...
Themanagementbelievesthat__________allofthedamagedgoodswillcostmor...
Accordingtonewsreports,personal__________ofgunsintheUSAcausesalot...
Agoodadvertisementoftenuseswords__________peopleattachpositivemeanings.A
Socialchangeislesslikelytooccurinasocietywherepeoplearequitesim...
根据下列内容,回答201-205题。 Inthelate1960s,manypeopleinNorthAmericaturnedth...
Sincepeoplearefondofhumor,itisaswelcomeinconversationas__________...
随机试题
根据支付结算法律制度的规定,下列关于挂失止付的表述中,正确的有()。 A、挂失
海上货物运输基本险包括()。 A.海上运输平安险 B.海上运输水渍险 C
当今人类中流行最广的虫媒病毒病是()。 A.乙型脑炎 B.森林脑炎 C.登
制备倒凹是为了 A.获得良好的抗力形 B.获得良好的固位形 C.便于垫底
关于宫内节育器的副反应,下列哪项错误?() A.出血常发生于放置宫内节育器后1
服用短效避孕药希望妊娠者,须在 A、停药后1个月 B、停药后2个月 C
健康危险因素干预的主要工作内容包括()
D第一组图形的共同点是每个符号都有“占”,第二组图形的共同点是都有“云”。
奥地利作家塞万提斯的《堂吉诃德》中的主人公是一个脱离实际、耽于幻想的人物。(
把课程分为必修课程和选修课程的依据是()