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
2016春冀教版英语七下Unit 7《Lesson 40 Move Your Body》word参考教案
2016春冀教版英语七下Unit 5《Lesson 26 Online Phone Calls》word精品教案
2016春冀教版英语七下Unit 7《Lesson 42 Know Yourself》word参考教案
2015秋冀教版英语七上Unit 1《Lesson 6 Things for School》课文重点整理
2016春冀教版英语七下Unit 8《Lesson 45 Baseball Season》word参考教案
2015秋冀教版英语七上Unit 3《Body Parts and Feelings》全单元教案
2016春冀教版英语七下Unit 8《Lesson 44 Volunteering in Summer》word参考教案
2016春冀教版英语七下Unit 5《Lesson 28 How Do I Learn English》word精品教案
2016春冀教版英语七下Unit 6《Lesson 36 Spring in China》word教案
2015秋冀教版英语七上Unit 2《Lesson 9 Whose Coat Is This》导学案
2015秋冀教版英语七上Unit 2《Lesson 7 Jennys New Skirt》导学案
2016春冀教版英语七下Unit 5《Lesson 25 A Phone Friend》word精品教案
2016春冀教版英语七下Unit 5《Lesson 29 A Door to the World》word精品教案
2015秋冀教版英语七上Unit 1《Lesson 6 Things for School》教案
2015秋冀教版英语七上Unit 1《Lesson 5 May I Have a Book》教案
2016春冀教版英语七下Unit 7《Lesson 41 Were People Healthy Then》word参考教案
2016春冀教版英语七下Unit 7《Lesson 38 Stay Healthy》word参考教案
2015秋冀教版英语七上Unit 1《Lesson 6 Things for School》导学案
2015秋冀教版英语七上Unit 1《Lesson 5 May I Have a Book》导学案
2016春冀教版英语七下Unit 8《Lesson 47 Summer Plans》word参考教案
2016春冀教版英语七下Unit 5《Lesson 27 Amazing English》word精品教案
2015秋冀教版英语七上Unit 2《Lesson 8 Danny’s Favourit Colour》导学案
2016春冀教版英语七下Unit 7《Sports and Good Health》word单元教案
2015秋冀教版英语七上Unit 3《Body Parts and Feelings》(Lessons 16-18)课文重点整理
2015秋冀教版英语七上Unit 3《Body Parts and Feelings》全单元学案
2015秋冀教版英语七上Unit 4《Food and Restaurants》(Lessons 19、20)导学案
2015秋冀教版英语七上Unit 2《Colours and Clothes》单元教案
2015秋冀教版英语七上Unit 4《Food and Restaurants》(Lessons 21、22)导学案
2015秋冀教版英语七上Unit 2《Colours and Clothes》(lesson 10-12)课文重点整理
2016春冀教版英语七下Unit 5《Lesson 30 Writing an E-mail in English》word精品教案
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |