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
Why So Many People Rush To Cities? 为什么那么多人想去城市?
Before hand? 事先
国际英语资讯:Africas confirmed COVID-19 cases surpass 115,000: Africa CDC
新冠疫情催生出一种新工作
想天空
技能培训助广西农民成功脱贫
生态环境部部长黄润秋回应环保关切
今年我国将实行积极的财政政策来对抗疫情冲击
渡手
狗也和人一样有青春期烦恼
Television 电视
口罩装上"机械嘴"吃饭时不用摘
35名人大代表联署议案:加快制定外国国家豁免法
Properly Discard 适当的舍弃
生态环境部部长黄润秋回应环保关切
体坛英语资讯:Chinese clubs and players mourn the passing of Radmiro Antic
Say No to Cyber-violence 向网络暴力说不
体坛英语资讯:Wuhan women footballers return to national team
体坛英语资讯:Antic got offers from China last year, Chinese media reports
国际英语资讯:Spotlight: Europeans continue to heal economic wounds, infections top 2 mln
体坛英语资讯:Kenya to spend more to prepare for 2021 Tokyo Games due to COVID-19
国际英语资讯:New York Stock Exchange partially reopens as U.S. COVID-19 deaths near 100,000
经济学家:中国的经济复苏将惠及东盟
体坛英语资讯:Ex-Chelsea midfielder Mikel mulling Botafogo move
体坛英语资讯:World Athletics confirm new dates for Oregon world championships 2022
体坛英语资讯:China football coach Li expects to call up more naturalized players, media reports
美文赏析:摔倒的小女孩
英语中的双关语:这些笑点,你get到了吗?
10个与时间有关的英语短语,让你的口语更地道!
体坛英语资讯:F1 official: 2020 season could be held behind closed doors
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |