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
“背包游”改变国人海外消费
教育部出台教师收受礼品礼金“六项禁令”
京东打“墙面广告”进军农村
世界杯球星“太太团”
国产埃博拉“检测试剂”获批文
“恶搞视频”舌尖泡面版你看过了吗?
中央政府采购“排除”外国反病毒产品
体坛英语资讯:Kenya ready for Indonesia Davis Cup tie
高考新政:文理不分科考“3+3”
“新能源汽车购置税”将免征
娱乐英语资讯:Mongolian rock band to receive highest state award
国际英语资讯:Brexit dominates UK election campaign
梅西终于“进球”了
体坛英语资讯:Kipchoges low-key return stumps media
“预测模型”助百度成为世界杯预测帝
国际英语资讯:Jordan, NATO?discuss means to boost ties
“门线技术”助法国队进球
体坛英语资讯:Gabon beat host Morocco 3-2 in soccer friendly
国际英语资讯:Pompeo says U.S. no longer considers Israels West Bank settlements against intl law
新版汉语词典收“土豪”弃“屌丝”
上海市民支持“广场舞”
北京将严控“天桥积水”
多地宣布放松“房屋限购”
国际英语资讯:Feature: Egypt marks Suez Canals 150th anniversary with artifact exhibition
国内英语资讯:Senior political advisor urges efforts for national reunification
越南“冲撞”中方船只
“中国戏曲”繁荣只是“昙花一现”
三亚发放“物价补贴”
“倒卖进京户口指标”团伙落网
深圳试水光速“海淘” 可代缴“行邮税”
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |