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【单选题】
ACID RAIN: What's the Solution? One of the wildest regions in the U.S., far from civilization, is the Adirondack area of northern New York State. For years this isolated spot has had the reputation of being one of best fishing spots in the U.S. As a boy 30 years ago, Bill Marleau first through the Adirondack wilderness near his small cabin on Woods Lake. Thousands of sportsmen have stayed at his father's lodge nearby. But now Bill's 134 hectares (335 acres) of lakefront land have only scenic value. Gone are those huge trout that used to swim in the turbulent, nutrientrich water a short distance from his doorstep. Gone from the cool nights are the sounds of thousands of frogs and toads. And gone are the birds that once fed on those water creatures. Occasionally Bill sees a lone fisherman fruitlessly cast his bait into the empty waters of old lake. 'I just don't have the heart to tell,' he said. 'This old lake's dead. It was killed years ago by acid rain.' What is acid rain? Acid rain is a popular term for precipitation in the form. of rain, sleet, snow or hail that is more acidic than normal. Acid rain is produced when atmospheric moisture combines with pollutants from power plants, factories and automobiles. When fossil fuels such as coal and oil are burned, sulfur dioxide and nitrogen dioxide are produced. These two gases react with the water and oxygen in the atmosphere to form. droplets of weak sulfur and nitric acid. Carried by prevailing winds and weather conditions, clouds containing these droplets travel hundreds, sometimes thousands, of kilometers from the source of the pollutants. Recently scientists found that acid rain now affects huge areas of the North Hemisphere. Power plants and factories in the heavily industrialized regions of Ohio and Indiana are believed to be the source of the acid rain that killed Woods Lake along with hundreds of others in New York State and eastern Canada. Acid haze over Alaska is believed to come all the way from Japan. And precipitation as acid as vinegar that falls on Scotland and Scandinavia probably originates in England. How Acidity Is Measured Scientists measure the acidity of rain in pH units. A pH scale from 0 to 14 is used. Depending upon its chemical composition, a solution is either acidic, alkaline (basic), or neutral. Distilled water, which has a pH of 7, is neutral. Substance with pH values less than 7 are acidic, while those over 7 are alkaline. Normal rain water with a pH of 5.6 is slightly acidic. But after reacting with industrial pollutants, particularly sulfur dioxide, the pH of rain quickly drops. When acid rain falls to Earth, much of it ends up in lakes and ponds. In addition to failing directly into a lake, acid rains runs off land into streams and rivers that eventually flow into lakes and ponds. Once acid rain gets into them, its effects can be deadly. Studies started in 1975 in the Adirondacks indicate that salamanders and frogs are the first to die when the pH is lowered. Normally the pH of a lake is 8,0 slightly alkaline. When the pH drops to 7, the eggs of salamanders and frogs fail to hatch. At pH 6.6 snails begin to die. Bacteria that decompose leaf matter die too, and the leaf matter collects on the lake bottom. As the acidity continues to drop, ail the major food chains in the lake become affected. In time all the fish die. Eventually primitive, oxygenconsuming plants nearly choke out all other aquatic greenery. Algae and fungal growth that thrive in an acidic environment move in and cover the entire bottom of the now destroyed lake. Looking like blue vinegar, the lake is now an entirely changed ecosystem. It contains no life expect the fungal and algal growth and a few surfacedwelling water bugs. &n
A.
Y
B.
N
C.
NG
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【单选题】心电图上表示冲动从心房传导到心室的时间是
A.
U波
B.
QRS波
C.
T波
D.
P波
E.
P-R间期
【多选题】以下有关明细分类科目的表述,正确的是( )。
A.
能提供更加详细、具体的会计信息的科目
B.
除国家统一会计制度规定设置的以外,各单位可以根据实际需要自行设置
C.
也称一级会计科目
D.
是对总分类科目作进一步分类的科目
【判断题】光学显微镜的光学系统由物镜、目镜、聚光器等组成,直接影响着显微镜的性能,是显微镜的核心。
A.
正确
B.
错误
【单选题】有人把速写比作( )。
A.
“望远镜” 和 “显微镜”
B.
“ 凸透镜 ”和“凹透镜”
C.
“ 照相机”和“拍立得”
D.
“复印机”和“打印机”
【单选题】如上图所示,标准II导联记录到到正常的心电图,P波代表
A.
心房肌细胞去极
B.
心房肌细胞复极
C.
心室肌细胞去极
D.
心室肌细胞复极
【多选题】以下有关明细分类科目的表述中,正确的是
A.
能提供更加详细、具体的会计信息的科目
B.
除国家统一会计制度规定设置的以外,各单位可以根据实际需要自行设置
C.
也称一级会计科目
D.
是对总分类科目作进一步分类的科目
【单选题】心电图上表示冲动从心房传导到心室的时间是
A.
P波
B.
P-R间期
C.
QRS波
D.
T波
E.
U波
【单选题】有人曾这样写道:英国艺术家画出了汽车的速度,德国作曲家把蒸汽船的噪音变成了音乐。而在18—19世纪,欧洲、美国作家写下了大批反映和描写“自然”的诗歌和其他文艺作品,他们擅长运用比喻、拟人的修辞手法宣传其主张,如“地球(自然)是人类的母亲”“自然发怒”等。材料反映了人们()
A.
对工业文明的向往、赞美及担忧
B.
对社会发展的浪漫主义情怀
C.
对自然风光的无限向往与想象
D.
对科技革命的期盼与幻想
【简答题】心电图上P波表示——
【多选题】下列关于利息和利率的说法,不正确的是()。
A.
利率的高低首先取决于社会平均利润率
B.
利息和利率是以信用方式动员和筹集资金的动力
C.
利率的高低总是取决于金融市场上借贷资本的供求情况
D.
通货膨胀对利息的波动有间接影响
E.
利息和利率是国家经济管理的重要杠杆
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