【单选题】
In this part there are four passages for you to reaD、After each passage there are five questions, below each of whom there are four answers markedA,B,
C、andD、Choose the best answer and mark the corresponding letter with a pencil on the Machine-ScoringAnswer Sheet with a single line through the center.
The United StatesArmy has now determined that the glare from snow does not cause snow-blindness in troops in a snow-covered country. Rather, a man’s eyes frequently find nothing to focus on in a broad expanse of a snow-covered area So his gaze continually shifts and jumps back and forth over the entire landscape in search of something to look at. Finding nothing, hour after hour, the eyes never stop searching and the eyeballs become sore and the eye muscle aches. Nature balances this annoyance by producing more and more liquid which covers the eyeballs. The liquid covers the eyeballs in increasing quantity until vision blurs.And the result is total, even though temporary, snowblindness.
Experiments led theArmy 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 searching through the snow-blanketed landscape.By focusing their attention on one object at a time, the man can cross the snow without becoming hopelessly snowblind or lost. In this way the problem of crossing a solid white area is overcome.
B．Nature’ sCure for Snowblindness
C、Soldiers in the Snow
D．Snow Vision
网考网参考答案：A
网考网解析：
[解析] 雪盲及如何避免雪盲是文章的主题，A为正确答案。 document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>
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