Many people believe the glare from snow causes snowblindnenss. 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 glare from snow does not cause snowblindness in troops in a snow-covered country.Rather, a mans eyes frequently find nothing to foucs 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 tsomething to look at. Finding nothing, hour after hour, the eyes never sotp 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 coversthe eyeball in increasing quantity until vision blurs, then is obsured,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 scouring the snow-blanketed lanscape. By focusing their attention on one object at a time,the men can cross the snow without becoming hopelessly snowblind or lost. In this way the problem of crossing a solid white terrain is overcome.
1.To prevent headaches, watering eyes and blindness caused by the glare from snow, dark glasses are_____.
A.indispensible
B.useful
C.ineffective
D.available
2.When the eyes are sore tears are produced to ________.
A.clear the vision
B.remedy snowblindness
C.ease the irritation
D.loosen the muscles
3.Snowblindness may be avoided by_______.
A.concentrating to the solid white terrain
B.searching for something to look at in snow-covered terrain
C.providing the eyes with something to foucs on
D.covering the eyeballs with fluid
4.The scouts shake snow from evergreen bushes in order to _______.
A.bive the men behind something to see
B.beautify the landscape
C.warm themselves in the cold
D.prevent the men behind from losing their way
5.A suitable title for this passage would be _______.
A.snowblindness and how to overcome it
B.natrues cure for snowblindness
C.soldiers in the snow
D.snow vision
答案:CCCAA
中国爸爸,你们认为最重要的家务是啥?
西班牙男子忆“狼人”童年生活
黑色星期五:顾客为抢毛巾大打出手
美亿万富翁宣布2017年载人赴火星
办公室恋情行不行:只要是上司就行
青少年艾滋病毒感染者十年上升33%
只剩30天:年底前必须完成的3件事
美国一位父亲称在谷歌地图中看到去世的儿子
骆驼也卖萌!不请自来与主人共进早餐
印度官员创立婚恋网站 助艾滋病感染者成婚者
感人视频:顽强小宝宝成长的一年
三只小熊现实版:手拉手跳圆圈舞
英4岁女孩被宠物狗袭击后死亡
担心战时影响发射速度 美国核弹发射密码曾为8个0
你的大脑能“招架”多少朋友?
不离不弃!男子灾后废墟中救爱犬
Kid President:我们该常说的20句好话
美国宇航员登月曾寻嫦娥:带大兔子的可爱姑娘
熟女注意!女性做临时工难怀孕?
已到扔掉绿卡时 美国退籍者与日俱增
凛冬已至!关于冬季保暖的10件事
国际英语资讯:Brazilian govt announces campaign to boost retail sales
嫦娥三号发射成功 展开奔月之旅
BBC看中国:仅6%中国人表示对工作很投入
美貌是如何形成的?
俄罗斯客机坠毁致50人死亡 鞑靼共和国总统之子遇难
国足运动员郑智荣膺亚洲足球先生
控制狂老板?不造反不消极的沟通法
实用10招 和难相处的人们打交道
羡慕soho? 如何说服老板让你在家上班
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |