反馈控制系统的特点是不论什么原因使被控量偏离期望值，都会有相应的控制作用去减小或消除这个偏差。 ()

Part B (10 points)You are going to read a list of headings and a text about network etiquette. Choose the most suitable heading from the list for each numbered paragraph. The first and last paragraphs of the text are not numbered. There is one extra heading which you don't need to use.The first two stages in the development of civilized man were probably the invention of primitive weapons and the discovery of fire, although nobody knows exactly when he acquired the use of the latter.(41)______. Animals have a few cries that serve as signals, but even the highest apes have not been found able to pronounce words, even with the most intensive professional instruction. The superior brain of man is apparently a necessity for the mastering of speech. When man became sufficiently intelligent, we must suppose that he gradually increased the number of cries for different purposes. It was a great day when he discovered that speech could be used for narrative. There are those who think that in this respect picture language preceded oral language. A man could draw a picture on the wall of his cave to show in which direction he had gone, or what prey he hoped to catch. (42)______.Two important stages came not so long before the dawn of written history. The first was the domestication of animals; the second was agriculture. Agriculture made possible an immense increase in the number of the human species in the regions where it could be successfully practiced. (43)______.(44)______.These inventions and discoveries—fire, speech, weapons domestic animals, agriculture, and writing made the existence of civilized communities possible. From about 3000 B.C. until the beginning of the Industrial Revolution less than two hundred years ago there was no technical advance comparable to these. During this long period man had time to become accustomed to his technique, and to develop the beliefs and political organizations appropriate to it. There was, of course, an immense extension in the area of civilized life. At first it had been confined to the Nile, the Euphrates, the Tigris, and the Indus, but at the end of the period in question it covered much the greatest part of the inhabitable globe. I do not mean to suggest that there was no technical progress during the time. (45)______. 点击查看答案

财产权利和人身权利都具有可让与性。() 点击查看答案&解析