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问题 选择题

咸鱼能保存较长的时间，其原因是（　　）

A．咸鱼已煮熟，营养很少，不利于细菌、真菌的生长、繁殖

B．细菌真菌不喜欢分解有腥味的鱼肉

C．鱼肉内加入了盐以外的防腐剂

D．咸鱼表面缺水、鱼肉内有大量的盐分，不利于细菌、真菌的生存繁殖

答案

因食物腐败变质是由于微生物的生长和大量繁殖而引起的．根据食物腐败变质的原因，食品保存就要尽量的杀死或抑制微生物的生长和大量繁殖，传统的食品保存方法有盐腌、糖渍、干制、酒泡等．现代的贮存方法主要有罐藏、脱水、冷冻、真空包装、添加防腐剂等．咸鱼能存放长久的原因是在高盐分的情况下细菌繁殖速度很慢，不利于细菌、真菌的生存繁殖．

故选：D

单项选择题

有以下程序main(){ union{ char ch[2];int d;}s;s.d=0x4321;printf("%x,%x\n",s.ch[0],s.ch[1]);}在16位编译系统上，程序执行后的输出结果是______。

A．21,43

B．43,21

C．43,00

D．21,00
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问答题

It is hard to predict how science is going to turn out, and if it is really good science it is impossible to predict. If the things to be found are actually new, they are by definition unknown in advance. You cannot make choices in this matter. (46) You either have science or you don’t, and if you have it you are obliged to accept the surprising and disturbing pieces of information, along with the neat and promptly useful bits.
The only solid piece of scientific truth about which I feel totally confident is that we are profoundly ignorant about nature. Indeed, I regard this as the major discovery of the past hundred years of biology. It is, in its way, an illuminating piece of news. (47) It would have amazed the brightest minds of the 18th century Enlightenment to be told by any of us how little we know and how bewildering the way ahead seems. (48) It is this sudden confrontation with the depth and scope of ignorance that’ represents the most significant contribution of the 20th century science to the human intellect. In earlier times, we either pretended to understand how things worked or ignored the problem, or simply made up stories to fill the gaps. Now that we have begun exploring in earnest, we are getting glimpses of how huge the questions are, and how far from being answered. Because of this, we are depressed. (49) It is not so bad being ignorant if you are totally ignorant the hard thing is knowing in some detail the reality of ignorance, the worst spots and here and there the not so bad spots, but no true light at the end of the tunnel nor even any tunnels that can yet be trusted.
But we are making a beginning and there ought to be some satisfaction. There are probably no questions we can think up that can’t be answered, sooner or later, including even the matter of consciousness. (50) To be sure, there may well be questions we can’t think up, ever, and therefore limits to the reach of human intellect, but that is another matter. Within our limits, we should be able to work our way through to all our answers if we keep at it long enough, and pay attention.
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