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
Many people believe the glare from snow causes snow blindness. Yet, dark glasses or not they find themselves suffering from head
Many people believe the glare from snow causes snow blindness. Yet, dark glasses or not they find themselves suffering from head
admin
2012-07-18
47
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 snowblindness, when exposed to several hours of "snow light".
The United States Army has now determined that the 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 a snow-covered area. 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 muscle aches. Nature balances this annoyance by producing more and more liquid which covers the eyeballs. The liquid covers the eyeballs in increasing quantity until vision blurs . And the result is total, even though temporary, snowblindness.
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 searching through the snow-blanketed landscape. By focusing their attention on one object at a time, the man can cross the snow without becoming hopelessly snowblind or lost. In this way the problem of crossing a solid white area is overcome.
The first paragraph is mainly concerned with_____.
选项
A、snow glare and snowhlindness
B、the whiteness from snow
C、headaches, watering eyes and snowblindness
D、the need for dark glasses
答案
A
解析
雪的强光(snow glare)以及雪盲(snowblindness)是这篇谈论的重点,因此选择A答案。
转载请注明原文地址:https://kaotiyun.com/show/wanO777K
0
考博英语
相关试题推荐
Hewaswidelyregardedasa______manbecauseherevealeddailyhisdistrustofhumannatureandhumanmotives.
AttheKyotoconferenceonglobalwarminginDecember1997,itbecameabundantlyclearhowcomplexithasbecometoworkoutint
AttheKyotoconferenceonglobalwarminginDecember1997,itbecameabundantlyclearhowcomplexithasbecometoworkoutint
AttheKyotoconferenceonglobalwarminginDecember1997,itbecameabundantlyclearhowcomplexithasbecometoworkoutint
Thesourcesofanti-Christianfeelingweremanyandcomplex.Onthemoreintangibleside,therewasageneralpiqueagainstthe
Hegavehisworktohisfriendto______,becausehefoundithardtoseehisownmistakes.
Nowthatinscientificcommunitiestheuseofcomputersiswidespread,andsupposingthatthereissufficienttime,thereexist
Humanlikeanimalbehaviorhasastrikingeffect.Dogsandeatsbolsterourmoraleandmakeusfeelspecial,becausetheyofferu
随机试题
巨大儿对母体可能的影响有
根据我国法律规定,涉外不动产物权民事争议,应适用()
A.奶及奶制品B.猕猴桃C.动物肝脏D.粮谷类E.马铃薯富含铁的食物是
下列哪项不是绿化的作用
患者女,70岁,无牙颌,全口义齿修复后1个月。主诉咀嚼费力,咀嚼肌易酸痛。患者还可能存在的临床表现是
西洋参的来源和成分为
利用烘干法测定水分的药物有()
屋面高聚物改性沥青防水卷材的常用铺贴方法有()。
下列项目管理工作中,不属于施工方项目管理任务的是()。
完整地表述了公安工作中党的领导、公安机关和人民群众三者的关系,反映我国公安工作的重要特色和优势的理论是()。
最新回复
(
0
)