Drug use is rising dramatically among the nation’ s youth after a decade of decline. From 1993 to 1994, marijuana use among young people (1) from 12 to 17 jumped 50 percent. One in five high school seniors (2) marijuana daily. Monitoring the Future, which (3) student drug use annually, reports that negative attitudes about drugs have declined for the fourth year in a row. (4) young people see great risk in using drugs. Mood-altering pharmaceutical drugs are (5) new popularity among young people. Ritalin, (6) as a diet pill in the 1970s and now used to (7) hyperactive children, has become a (8) drug on college campuses. A central nervous system (9) , Ritalin can cause strokes, hypertension, and seizures. Rohypnol, produced in Europe as a (10) tranquilizer, lowers inhibitions and suppresses short-term memory, which has led to some women being raped by men they are going out with. (11) taken with alc
A. More
B. Many
C. Fewer
D. Few
Our daily existence is divided into two phases, as distinct as day and night. We call them work and play. We work many hours a day and we allow the necessary minimum for such activities as eating and shopping. 46) The rest we spend in various activities which are known as ecreations, an elegant word which disguises the fact that we usually do not even play in our hours of leisure, but spend them in various forms of passive enjoyment or entertainment.
We need to make, therefore, a hard-and-fast distinction not only between work and play but, equally, between active play and passive entertainment. 47) It is, I suppose, the decline of active play--of amateur sport--and the enormous growth of purely receptive entertainment which have given rise to a sociological interest in the problem. If the greater part of the population, instead of indulging in sport, spend their hours of leisure "viewing" television programs, there will inevitably be a decline in
计算题:
用硝酸银滴定法测定水中氯化物的含量,用0.0141mol/L氯化钠标准溶液25.0ml,加入25.0ml蒸馏水后,对一新配制的硝酸银标准溶液进行标定,用去硝酸银溶液24.78ml,已知空白消耗硝酸银溶液0.25ml,问硝酸银溶液浓度是多少?假如用其测定水样,50.0ml水样消耗了硝酸银标液5.65ml,则此水样中氯化物含量多少(氯离子的摩尔质量为35.45)
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