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
2011-06-29
41
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 eyeballs become sore and the eye muscles ache because______.
选项
A、tears cover the eyeballs
B、the eyes are annoyed by blinding sunlight
C、the eyes are annoyed by blinding snow
D、there is nothing to focus on
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/iv6O777K
0
考博英语
相关试题推荐
Areyoualwayssureyouknowwhatpeoplemeanwhentheytrytodescribetheirfeelingstoyou?Weusebothwordsandgesturesto
Therearesome______betweentheirtwodescriptions;wearepuzzledwhichweshouldbelieve.
Surprisinglyenough,modernhistorianshaverarelyinterestedthemselvesinthehistoryoftheAmericanSouthintheperiodbefo
Whatdoconsumersreallywant?That’saquestionmarketresearcherswouldlovetoanswer.Butsincepeopledon’talwayssaywhat
(46)HomescouldstartbeenconnectedtotheInternetthroughelectricaloutlets.(47)Inthisway,consumersandbusinessmayf
(46)HomescouldstartbeenconnectedtotheInternetthroughelectricaloutlets.(47)Inthisway,consumersandbusinessmayf
中国的饮食方式正在发生许多变化。众所周知,中国的饮食文化具有悠久的历史。人们采用肉、蔬菜、豆制品等能做出各种美味食品,但往往耗时多。这一点与快节奏的现代社会极不相符。如今我们有了许多不同的选择:除传统家常菜外,还有营养保健配餐和方便可口的快餐食品。由于午休
推进现代化建设、完成祖国统一、维护世界和平与促进共同发展,是中国人民在新世纪的三大历史任务。
TheUKgovernmenthassomewaytogoinbuildingtrustinitshandlingofgeneticmodificationinagriculture.Lessonslearn
Someweeksago,ridinginacabfromBostontoCambridge,mydriverturnedandaskedmewhatIdidforaliving."TeachEnglish,
随机试题
下列描述真空采血不正确的是
下列私募基金的募集行为错误的是()。
一般而言,宽松的货币政策有助于刺激投资需求增长,导致()。
(2002年考试真题)甲股份有限公司2001年有关资料如下:(1)当期销售商品实现收入100000元;应收账款期初余额20000元,期末余额50000元;预收账款期初余额10000元,期末余额30000元。假定不考虑坏账准备和增值税因素。(2)当期用银
简述尝试一错误学习的基本规律。
调查研究法是有目的、有计划、有系统地收集有关研究对象的现实状况或历史状况的材料,发现问题、揭示事物的规律,找出解决问题的办法。()
用户打开名为“个人简历”的Word文件,通常是指();若再单击常用工具栏上的“()”按钮,可以插入表格。
Hewassorrythathehadbeenimpolitetoher.Heregretted____________.
ThefirstfarmanimalJackever【51】fromastockyardwasalamb【52】Hida.aamSanctuary,180acresofveganheavenintheFingerL
Sofartheresearchhassuggestedthatonlytheemotionaleffectsofmemoriesmaybereduced,notthatthememoriesareerased.
最新回复
(
0
)