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
近三年高考(2017-2016)英语试题分项版解析:专题03 形容词和副词(原卷版)
2017届高考英语大一轮复习课件:必修5 unit3 Life in the future(新人教版)
三年高考(2017-2015)英语试题分项精析版:专题02 代词、介词和介词短语(原卷版)
2017届高考英语大一轮复习课件:选修6 unit4 Global warming(新人教版)
近三年高考(2017-2016)英语试题分项版解析:专题05 动词的时态和语态(原卷版)
2017届高考英语大一轮复习课件:选修7 unit1 Living well(新人教版)
三年高考(2017-2015)英语试题分项精析版:专题09 连词和状语从句(原卷版)
2017届高考英语大一轮复习课件:选修7 unit3 Under the sea(新人教版)
三年高考(2017-2015)英语试题分项精析版:专题04 动词和动词短语 (原卷版)
2017届高考英语大一轮复习课件:选修8 unit4 Pygmalion(新人教版)
2017届高考英语大一轮复习课件:选修8 unit3 Inventors and inventions(新人教版)
三年高考(2017-2015)英语试题分项精析版:专题10 名词性从句(解析版)
三年高考(2017-2015)英语试题分项精析版:专题08 定语从句(原卷版)
三年高考(2017-2015)英语试题分项精析版:专题05 动词的时态和语态(原卷版)
三年高考(2017-2015)英语试题分项精析版:专题11 特殊句式(原卷版)
2017届高考英语大一轮复习课件:选修8 unit1 A land of diversity(新人教版)
三年高考(2017-2015)英语试题分项精析版:专题12 交际用语(原卷版)
日本公司提供假朋友 让你在社交网络“有面子”
2017届高考英语大一轮复习课件:选修6 unit3 A healthy life(新人教版)
2017届高考英语大一轮复习课件:选修8 unit2 Cloning(新人教版)
2017届高考英语大一轮复习课件:选修8 unit5 Meeting your ancestors(新人教版)
2017届高考英语大一轮复习课件:必修5 unit4 Making the news(新人教版)
近三年高考(2017-2016)英语试题分项版解析:专题04 动词和动词短语(原卷版)
近三年高考(2017-2016)英语试题分项版解析:专题07 非谓语动词(解析版)
近三年高考(2017-2016)英语试题分项版解析:专题01 冠词、名词和主谓一致(解析版)
2017届高考英语大一轮复习课件:选修7 unit2 Robots(新人教版)
2017届高考英语大一轮复习课件:必修4 unit4 Body language(新人教版)
Kept his wits about?
近三年高考(2017-2016)英语试题分项版解析:专题02 代词、介词和介词短语(原卷版)
三年高考(2017-2015)英语试题分项精析版:专题01 冠词、名词和主谓一致(原卷版)
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |