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
卫计委:5年后每个家庭拥有一名签约“家庭医生”
In a brown study: 沉思
“不耗电屏幕”:手机每周只充一次电
小朋友都喜欢的“潘克族”
Skid row: 贫民窟
李克强在第四次中国-中东欧国家领导人会晤上的讲话
Crotchety: 钩子;怪念头
中国文化词汇:古代典籍
以分钟计算的“克强节奏”
伦敦咖啡店禁止顾客穿雪地靴
路易威登新款鳄鱼皮包贵过奔驰车
你不知道的十部感恩节主题电影
有了这些替换词再不怕词穷了
Ginormous: 特大,无比大
“针织涂鸦”现身魔都
Sundae: “圣代”冰激凌
Fair dinkum: 真实的,光明正大的
Teen: 少年
研究:会说双语有助中风康复
By and large: 总体上来说
怎样幽默地表达感谢
六句话学会fine line用法
妆容新潮流:雀斑DIY
研究称智能设备让时间变快了
脸书男员工将有四个月陪产假
Lapidary: 简洁优雅的
Charlatan: 江湖郎中
Pine: 憔悴
Madcap: 疯子
习近平定调国防和军队改革
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |