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
58
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
阳经的交接部位在 A.头 B.胸 C.腹 D.背 E.足
碳酸锂的最佳适应证为 A.典型躁狂发作 B.混合性躁狂发作 C.快速循环型
商业银行在不良资产处置中应综合考虑不良资产类型、债务关联人偿债意愿和偿还能力、市
小张在出差之前要求公司为其投一份意外伤害险,小张的行为属于( )。
碱性最强的生物碱类型是
标准通用化的一个重要指导思想是通用化的实施应从产品()时开始。 A
当代世界城镇化的特点是()。 A.城镇化进程大大降低,发展中国家逐渐成
大雁成“人”字形飞,相同的能量下,群飞能够比单独飞多飞70%的路程,对此你怎么看?
由两种风险资产构建的组合的可行投资组合集表现为一条()。A.直线B.折线C.抛物线D.平行线
在施工现场生活区一般会搭建大量的供人员办公、住宿的临时用房,以下对临时搭建的宿舍、办公用房防火要求正确的是()。A.建筑层数不应超过3层,每层建筑面积不应大