问题 选择题

单细胞生物对人类(  )

A.都是有害的

B.都是有利的

C.即有有利的一面,又有有害的一面

D.无影响

答案

单细胞生物虽然个体微小,但是与人类的生活有着密切的关系.多数单细胞生物是浮游生物的组成部分,是鱼类的天然饵料.草履虫对污水净化有一定的作用,据统计,一只草履虫每小时大约能形成60个食物泡,每个食物泡中大约含有30个细菌,因此,一只草履虫每天大约能吞食43000个细菌.但是单细胞生物也有对人类有害的一面,如疟原虫,痢疾类变形虫等人体内寄生虫危害人类健康;海水中的某些单细胞生物大量繁殖可能造成赤潮.简单地说,单细胞生物与人类的关系可以分为有利和有害两个方面,有利:鱼类饵料、净化污水等,有害:危害健康,造成赤潮等.

故选:C

判断题
问答题

Most of the idle rich suffer unspeakable boredora as the price of their freedom from drudgery. At times they may find relief by hunting big game in Africa, but the number of such sensations is limited, especially after youth is past. 46. Accordingly more intelligent rich men work nearly as hard as if they were poor, while rich women mostly keep themselves busy with innumerable trifles of whose earth- shaking importance they are firmly persuaded.

47. Work is desirable as a preventive of boredom, for the boredom a man feels when doing necessary though uninteresting work is as nothing in comparison with the boredom he feels when having nothing to do. With this advantage of work another is associated, namely that it makes holidays much more delicious when they come. 48. Provided a man does not have to work so hard as to impair his vigor, he is likely to find far more zest in free time than an idle man could possibly find.

The second advantage of most paid work and of some unpaid work is that it gives chances of suecess and opportunities for ambition. In most work success is measured by income and while our capitalistic society continues, this is inevitable. It is only where the best work is concerned that this measure ceases to be the natural one to apply. 49. The desire that men feel to increase their income is quite as much a desire for success as for the extra comforts that a higher income can procure. However dull work may be, it becomes bearable if it is a means of buihliug up a reputation, whether in the world at large or only in one’ s own circle. Continuity of purpose is one of the most essential ingredients of happiness in the long run, and for most men this comes chiefly through their work.

50. The satisfaction of killing time and of affording some outlet, however modest, for ambition, belongs to most work, and is sufficient to make even a man whose work is dull happier on the average than a man who has no work at all. But when work is interesting, it is capable of giving satisfaction of a far higher order than mere relief from tedium. The kinds of work in which there is some interest may be arranged in a hierarchy. I shall begin with those which are only mildly interesting and end with those that are worthy to absorb the whole energies of a great man.

49. The desire that men feel to increase their income is quite as much a desire for success as for the extra comforts that a higher income can procure.