A buld-it-yourself solar still（蒸馏器）is one of the best ways to obtain drinking water in areas where the liquid is not readily available. Developed by two doctors in the U.S. Department of Agriculture, it’s an excellent water collector. Unfortunately, you must carry the necessary equipment with you, since it’s all but impossible to find natural substitutes. The only components required, though, are a 5'×5' sheet of clear or slightly milky plastic, six feet of plastic tube, and a container — perhaps just a drinking cup — to catch the water. These pieces can be folded into a neat little pack and fastened on your belt.
To construct a working still, use a sharp stick or rock to dig a hole four feet across and three feet deep. Try to make the hole in a damp area to increase the water catcher’s productivity. Place your cup in the deepest part of the hole. Then lay the tube in place so that one end rests all the way in the cup and the rest of the line runs up — and out — the side of the hole.
Next, cover the hole with the plastic sheet, securing the edges of the plastic with dirt and weighting the sheet’s center down with a rock. The plastic should now form a cone (圆锥体) with 45-degree-angled sides. The low point of the sheet must be centered directly over, and no more than three inches above, the cup.
The solar still works by creating a greenhouse under the plastic. Ground water evaporates (蒸发) and collects on the sheet until small drops of water form, run down the material and fall off into the cup. When the container is full, you can suck the refreshment out through the tube, and won’t have to break down the still every time you need a drink.
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答案
D
解析
细节理解题．根据文章随后一段第二句 Ground water evaporates and collects on the sheet until small drops of water form, run down the material and fall off into the cup 可知，地面上的水蒸发并且在塑料布上，形成小水滴后落在杯子里，因此可以得知水滴来自塑料布下方，故正确答案为D． 根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。 If anyone had told me three years ago that I would be spending most of my weekends camping. I would have laughed heartily. Campers, in my eyes, were people who enjoyed insect bites, ill-cooked meals, and uncomfortable sleeping bags. They had nothing in common with me. 36 . The friends who introduced me to camping thought that it meant to be a pioneer. 37 We sleep in a tent, cooked over an open fire, and walked a long distance to take the shower and use the bathroom. This brief visit with Mother Nature cost me two days off from work, recovering from a bad case of sunburn and the doctor’s bill for my son’s food poisoning. I was, nevertheless, talked into going on another fun-filled holiday in the wilderness. 38 Instead, we had a pop-up camper with comfortable beds and an air conditioner. My nature-loving friends had remembered to bring all the necessities of life. 39 We have done a lot of it since. Recently, we bought a twenty-eight-foot travel trailer complete with a bathroom and a built-in TV set. There is a separate bedroom, a modern kitchen with a refrigerator. The trailer even has matching carpet and curtains. 40 It must be true that sooner or later, everyone finds his or her way back to nature. I recommend that you find your way in style. A. This time there was no tent. B. Things are going to be improved. C. The trip they took me on was a rough one. D. I was to learn a lot about camping since then, however. E. I must say that I have certainly come to enjoy camping. F. After the trip, my family became quite interested in camping. G. There was no shade as the trees were no more than 3 feet tall.