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 exposedto 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 man's eyes frequently find nothing to foucs on in abroad 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 afterhour, 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 fluidcoversthe 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 theycross 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. Theirgaze 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 crossthe 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 ________.
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. natrue's cure for snowblindness
c. soldiers in the snow
d. snow vision英语四级仔细阅读模拟题答案
Water problems in the future will become nore intense and more complex. Our increasing population will tremendously increase urban wastes, primarily sewage. On the other hand, increasingdemands for water will decease substantialy the amount of water available for diluting wastes. Rapidly expanding industries which involve more and more complex chemical processes will producelarge volumes of liquid wastes, and many of these will contain chemicals which are noxious. To feed our rapidly expanding population, agriculture will have to be intensified. This will involveever-increasingquantities of agricultural chemicals, From this, it is apparent that drastic steps must be taken immediately to develop corrective measures for the pollution problem.
There are two ways by which this pollution problem can be dwindled. The first relates to the treatment of wastes to decrease their pollution hazard. This involves the processing of solidwastes "prior to" disposal and the treatment of liquid wastes, or efflunets, to permit the reuse of the water or minimize pollution upon final disposal.
A second approach is to develop an economic use for all or a part of the wastes. Farm manure is spread in fields as a nutrient or organic supplement. Effluents from sewage disposal plants areused in some areas both for irrigation and for the nutrients contained. Efflunets from other processing plants may also be used as a supplemental source of water. Many industries, such as meatand poultry processing plants, are currently converting former waste products into marketable byproducts. Other industries are potential eonomic uses for waste products.
1. The purpose of this passage is ________.
a. to alert the reader to the dwindling water supply
b. to explain industrial uses of water
c. to acquaint the reader with water pollution problems
d. to demostrate various measures to solve the pollution problem
2. Which of the following points is NOT INCLUDED in the passage?
a. In dustrial development incudes the simplification of complex chemical processes.
b. Diluting wastes needs certain amount of water
c. Demands for water will go up along with the expanding population
d. Intensive cultivation of land requires more and more chemicals
3. The reader can conclued that ________.
a. countries of the world will work together on polution problems
b. byproducts from wastes lead to a more prosperous marketplace
c. science is making great progress on increasing water supplies
d. some industries are now, aking economic use of wastes
4. The author gives substance to the passage through the use of ________.
a. interviews with authorities in the field of water controls
b. opinions and personal observations
c. definitions which clarify important terms
d. strong arguments and persuasions
5. The words "prior to"para.2 probably mean ________.