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
Gre填空词汇:积极与消极
Gre六选二近义词词汇总结54
Gre六选二近义词词汇总结62
Gre六选二近义词词汇总结58
GRE高级词汇背诵方法-助记法
Gre填空词汇:重视对轻视
Gre六选二近义词词汇总结73
GRE高级词汇背诵方法-形近义近归纳法
Gre填空词汇:显示对隐藏
Gre六选二近义词词汇总结78
Gre六选二近义词词汇总结91
Gre六选二近义词词汇总结89
Gre填空词汇:利益亏损与征服屈服
Gre六选二近义词词汇总结93
Gre六选二近义词词汇总结64
高效记忆gre词汇的3种方法
Gre填空词汇:服从跟抵抗
Gre六选二近义词词汇总结65
Gre六选二近义词词汇总结77
Gre填空词汇:获得跟丧失
Gre六选二近义词词汇总结76
Gre六选二近义词词汇总结79
Gre六选二近义词词汇总结68
Gre填空词汇:激动与平静
Gre词汇:单词记忆口诀整理le/te系列
Gre填空词汇:永恒对短暂
Gre填空词汇:复杂
Gre六选二近义词词汇总结80
Gre填空词汇:创新跟保守
Gre词汇:ab-/ac-等同辅音记忆方法
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |