“八月桂花十里飘香”，桂花盛开，很远就能闻到芳香馥郁，说明了分子的什么性质（ ）
A．分子的质量很小
B．分子间有间隔
C．分子在不停地运动
D．分子的体积很小
A、桂花飘香不能说明分子质量很小，此项错误．
B、桂花飘香不能说明分子间有间隔，此项错误．
C、飘香说明构成桂花的分子在不断运动，运动到人的鼻孔，刺激人的嗅觉细胞使人闻到香味，故此项正确．
D、闻到桂花的花香也不能说明分子体积很小，此项错误．
故选C
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| Most worthwhile careers require some kind of specialized training. Therefore, the choice of an 1 should be made even before choice of a curriculum in high school. Actually, 2 , most people make several job choices during their working lives, 3 because of economic and industrial changes and partly to improve 4 position. The "one perfect job" does not exist. Young people should 5 enter into a broad flexible training program that will 6 them for a field of work rather than for a single 7 . Unfortunately many young people have to make career plans 8 benefit of help from a competent vocational counselor or psychologist. Knowing 9 about the occupational world, or themselves for that matter, they choose their lifework on a hit-or-miss 10 . Some drift from job to job. Others 11 to work in which they are unhappy and for which they are not fitted. One common mistake is choosing an occupation for 12 real or imagined prestige . Too many high-school students - or their parents for them - choose the professional field, 13 both the relatively small percentage of workers in the professions and the extremely high educational and personal 14 . The imagined or real prestige of a profession or a White-collar job is 15 good reason for choosing it as life's work. 16 , these occupations are not always well paid. Since a large percentage of jobs are in mechanical and manual work, the 17 of young people should take serious 18 into these fields. Before making an occupational choice, a person should have a general idea of what he wants 19 life and how hard he is willing to work to get it. Some people des  ire social prestige, others intellectual satisfaction. Some want security; others are willing to take 20 for financial gain. Each occupational choice has its demands as well as its rewards. | ||||
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