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
每天吃多少最健康?手长度来帮忙测一测!
妹子们找高的吧!夫妇身高差和幸福感成正比
蠢哭:你是怎么弄坏你的笔记本的?
成功遭人嫉妒?这是最好的回答方式
美女们注意啦!记住这些,你的皮肤水嫩嫩!
老板再见!5种捷径外快赚够了就跑吧
路怒症成为交通事故的最大幕后黑手
低头党注意!常常玩手机的九大风险
你的身材勺形or桥形?正确站姿教你远离背痛
男性陪睡师新流行:我们也想要帅哥陪睡啊!
能创业的是老板 真正的企业家是这样
全球气候抗暖表现大评比:丹麦第一中国47
职场误区:营销人员嘴皮子溜就够了
新手必看:化妆达人也会犯的15个错误!
沙特土豪级斥资20亿建世界最高塔:超1千米
吃一口垃圾食品竟要运动这么久
真相:为了朋友圈装逼满格 我们拍照太拼了……
2017经济学人年度好书:知识改变命运
10部经久不衰的经典英国小说
世界网络哪家强?TOP20排行韩国第1香港第9
2016年度流行色发布:少女得不要不要的!
9个看似谎言的事实:你信吗?反正我信了
5个真相:解读新时代职业发展趋势
告诉你的老板!10招提升员工幸福感
致减肥的你:如何获得异性的青睐?
盘点那些慷慨捐赠的商界巨鳄
提前退休好不好
高颜值男性在职场易遭冷遇!
你以为所有的蔬果都能减肥吗
哪个猝不及防的瞬间你爱上了这个世界
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |