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
全优课堂2017届高考总复习当堂过关微测:必修1 unit 3《Travel journal》(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:选修6 unit 3《A healthy life》(新人教版含答案)
2017届高考英语一轮复习《全优课堂》写作技能步步高写作层级特训:要诀4.5.满分作文登场.邀请信(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:必修2 unit 4《Wildlife Protection》(新人教版含答案)
2017届高考英语一轮复习《全优课堂》写作技能步步高写作层级特训:要诀2.1 亮点词汇增色(新人教版含答案)
2017届高考英语一轮复习《全优课堂》核心语法项项破综合提能特训:专题7 定语从句(新人教版含答案)
2017届高考英语一轮复习《全优课堂》写作技能步步高写作层级特训:要诀3.3.高级句式添彩(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:必修5 unit 1《Great Scientists》(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:必修2 unit 1《Cultural relics》(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:必修3 unit 3《The Million Pound Bank-Note》(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:必修2 unit 3《Computers》(新人教版含答案)
2017届高考英语一轮复习《全优课堂》写作技能步步高写作层级特训:要诀3.5.高级句式添彩(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:必修5 unit 3《Life in the future》(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:必修1 unit 2《English around the world》(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:必修5 unit 2《The United Kingdom》(新人教版含答案)
2017届高考英语一轮复习《全优课堂》核心语法项项破综合提能特训:专题8 名词性从句(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:必修4 unit 4《Body Language》(新人教版含答案)
2017届高考英语一轮复习《全优课堂》写作技能步步高写作层级特训:要诀1 基本句型护航(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:必修4 unit 2《Working the land》(新人教版含答案)
2017届高考英语一轮复习《全优课堂》核心语法项项破综合提能特训:专题9 情态动词和虚拟语气(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:必修4 unit 3《A taste of English humour》(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:必修4 unit 1《Women of achievement》(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:必修2 unit 2《The Olympic Games》(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:必修3 unit 4《Astronomy:the science of the stars》(新人教版含答案)
2017届高考英语一轮复习《全优课堂》写作技能步步高写作层级特训:要诀4.1.满分作文登场(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:必修3 unit 2《Healthy eating》(新人教版含答案)
2017届高考英语一轮复习《全优课堂》核心语法项项破综合提能特训:专题6 并列句和状语从句(新人教版含答案)
2017届高考英语一轮复习《全优课堂》写作技能步步高写作层级特训:要诀3.1.高级句式添彩(新人教版含答案)
全优课堂2017届高考总复习当堂过关微测:必修1 unit 4《Earthquakes》(新人教版含答案)
2017届高考英语一轮复习《全优课堂》写作技能步步高写作层级特训:要诀2.2 亮点词汇增色(新人教版含答案)