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
77
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.
To prevent headaches, watering eyes and blindness caused by the glare from snow, dark glasses are__________.
选项
A. indispensible
B. useful
C. ineffective
D. available
答案
C
解析
根据第一段“Yet,dark glasses or not,they find themselves suffering from headaches and watering eyes。and even snow-blindness”可知,深色眼镜并不起作用,故选C。
转载请注明原文地址:https://ti.zuoweng.com/ti/zxk8KKKQ
相关试题推荐
WhichofthefollowingisNOTwhatHegelbelieved?A.Thecontentandformofthe
Peopleindifferentpartsoftheworldlearntounderstandonewithanother.A.d
TherearemuchmanymorepeoplethanIexpected.A.ThereB.muchC.manyD.than
Imetseveralpeoplethere,twoof______beingforeigners.A.whomB.themC.wh
Manypeoplebelievetheglarefromsnowcausessnow-blindness.Yet,darkglas...
Manypeoplebelievetheglarefromsnowcausessnow-blindness.Yet,darkglas...
Manypeoplebelievetheglarefromsnowcausessnow-blindness.Yet,darkglas...
Agoodadvertisementoftenuseswords__________peopleattachpositivemeanings.A
CarlSaganbelievesthatVenusmightbecolonizedfromearthbecause__________.A
MostpeopleagreethatthepresentroleofwomenhasalreadyaffectedU.S.so...
随机试题
患者,女,46岁。消瘦、右腰部疼痛2个月余,伴血尿20天,CT图像见图,最有可能
肺动脉造影最常做穿刺插管的血管是 A.股动脉 B.股静脉 C.肘动脉 D
工程咨询业主工程师全过程咨询服务的主要特点是()。
若一个基金管理人同时管理运作两个或两个以上的基金,则各只基金资产可以不分立账户。
某房地产开发公司购买一宗土地进行住宅开发,地价为l200万元,一次性付清。预计
第二级预防包括A.降低或减少劳动者接触职业性有害因素水平B.通过健康监护,早期发现职业损害C.建立和健全领导机构D.对职业病患者及时诊断和处理E.建立和
麻黄碱的结构属于A.酰胺类生物碱B.有机胺类生物碱C.异喹啉类生物碱D.莨菪烷类生物碱E.喹啉类产物碱
在某实验室中有以下药用辅料,可以用作片剂填充剂的有A.可压性淀粉B.微晶纤维素C.交联羧甲基纤维素钠D.硬脂酸镁E.糊精
某公司发行的股票,投资者要求的必要报酬率为15%,预计第一年每股发放股利0.5元,估计该公司股利每年的增长速度为5%,则该种股票的价值为( )元。A.5
春谦公司是一家家具生产企业,随着人们环保意识的加强,对木制家具的需求相比以前有所降低。春谦公司决定运用玻璃钢等材料对木材进行替代,研发出多款不需要木材的家...