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
24
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.
Snow-blindness may be avoided by_____.
选项
A、concentration on the solid white area
B、providing the eyes with something to focus on
C、searching for something to look at in snow-covered areas
D、covering the eyeballs with liquid
答案
B
解析
从第三段最后两句可知B为正确答案。
转载请注明原文地址:https://kaotiyun.com/show/uanO777K
0
考博英语
相关试题推荐
ItissaidthatthepublicandCongressionalconcernaboutdeceptivepackagingrumpusstartedbecauseSenatorHartdiscoveredth
IntheUnitedStatesandinmany【51】countriesaroundtheworld,therearefourmainwaysforpeopletobeinformed【52】develo
Before1500NorthAmericawasinhabitedbymorethan300culturalgroups,eachwithdifferentcustoms,socialstructures,world
Cooperativecompetition.Competitivecooperation.Confused?Airlineallianceshavetravelersscratchingtheirheadsoverwhat’s
Thesourcesofanti-Christianfeelingweremanyandcomplex.Onthemoreintangibleside,therewasageneralpiqueagainstthe
Duringthefamineof1943,millionsofChinesepeasants______tothecitiesbecausetheycouldnotsurviveintheruralareas.
______recentbrainandbehavioralresearch,Dr.Golemanwroteafascinatingbookentitled"EmotionalIntelligence."
Nowthatinscientificcommunitiestheuseofcomputersiswidespread,andsupposingthatthereissufficienttime,thereexist
Humanlikeanimalbehaviorhasastrikingeffect.Dogsandeatsbolsterourmoraleandmakeusfeelspecial,becausetheyofferu
Therearesomeearthphenomenayoucancounton,butthemagneticfield,somedayisnotofthem.Itfluctuatesinstrength,drif
随机试题
对关系S和R进行集合运算,结果中既包含s中的所有元组也包含R中的所有元组,这样的集合运算称为()。
在Excel2010中,D5单元格中有公式“=A5+$B$4”,删除第3行后,D4单元格中的公式是________。
女性,36岁,已婚。早孕药物流产后反复下腹坠痛5月,B超检查发现盆腔包块1月。妇科检查:子宫后位,正常大小,活动度差,左附件区可扪及一直径约6cm的包块,囊实性,与子宫分界不清,不活动,压痛,最可能的诊断是
诊断为治法为
由图7-58所示数字逻辑信号的波形可知,三者的逻辑关系是()。
假设某银行体系:(1)原始存款总额为100万;(2)法定准备金额为8%;(3)现金漏损率为10%;(4)超额准备金率2%;(5)定期存款准备金率为4%;(6)定期存款总额为20万元。根据以上材料,回答下列问题:对该银行体系存款创造的限制因
关于心理测验,正确的说法包括()。
下列选项中,正确地描述古希腊艺术美特征的是()
在社会主义国家,守法的主体有()
A、Tryingtokeeppacewithyournext-doorneighbors.B、Tryingtokeepincontactwithyourneighbors.C、Tryingtogetalongwell
最新回复
(
0
)