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
财务会计
Many people believe the glare from snow
Many people believe the glare from snow
恬恬
2019-12-17
52
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 terrainB. searching for something to look at in snow-covered terrainC. providing the eyes with something to focus onD. 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/eU49KKKQ
相关试题推荐
Imetseveralpeoplethere,twoof_____
Webelievethat_________recentchanges
Manypeoplebelievetheglarefromsnow
Manypeoplebelievetheglarefromsnow
Manypeoplebelievetheglarefromsnow
CarlSaganbelievesthatVenusmightbe
Mostpeopleagreethatthepresentrole
Sincepeoplearefondofhumor,itisas
Financialaidadministratorsbelievetha
Whydosomepeoplechooseself-catering
随机试题
下列情形中,属于直接向环境排放污染物从而应缴纳环境保护税的是()。 A.企业在
智齿冠周炎急性发作时治疗重点是 A.全身支持疗法 B.应用抗生素 C.药物
利率市场化是货币当局对利率的调控从直接管制方式转为间接调控方式的过程。()
关于钢结构防火涂料涂装的说法,正确的有()。
聚乙烯醇可在眼用液体制剂中用作()
下列哪项不是错层式(半坡道式)停车库的特点?( )
不属于ADL评定的内容的是
收益率是指投资金融工具所带来的收益与本金的比率,对理财规划师来说,收益率的正确计
根据《支付结算办法》的规定,下列属于支付结算和资金清算的中介机构是()。
五味中属于木的是A.酸B.苦C.甘D.辛E.咸