张力性气胸引起的主要病理生理改变是（）。 A.纵膈摆动 B.伤侧肺严重萎陷 C.反常

以下关于城建税的规定正确的是( )。

A．外国企业不缴纳城建税但是外商投资企业应缴纳城建税

B．个人在集市上出售商品所征收的临时经营的增值税，是否同时征收城建税由各省、自治区、直辖市人民政府根据实际情况确定

C．城市维护建设税的计税依据是纳税人增值税、消费税、营业税的应纳税额

D．海关对进口产品代征增值税、消费税的，也要代征城建税

体育课上小明和小李在玩篮球休息时他们讨论了一些关于打篮球时的物理问题，他们的讨论中说法不正确的是[ ]

A．投篮时，篮球离开手后继续向上运动，是因为篮球具有惯性

B．篮球从篮筐中下落时，速度逐渐加快，是因为重力的作用

C．静止在地面上的篮球，他所受的重力与篮球对地面的压力平衡

D．篮球撞在篮板上被弹回，是力改变了物体的运动状态

如何进行床层厚度与床压的关系试验？

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) ______
[A] Probably picture language and oral language developed side by side. I am inclined to think that language has been the most important single factor in the development of man.
[B] Another fundamental technical advance was writing, which, like spoken language, developed out of pictures, but as soon as it had reached a certain stage, it was possible to keep records and transmit information to people who were not present when the information was given.
[C] With the development of civilization, primitive people who lived in caves at that time badly needed a language, which would help them to communicate with one another.
[D] The origin of language is also obscure. No doubt it began very gradually.
[E] In fact, there was progress--there were even two inventions of very great importance, namely, gunpowder and the mariner’s compass—but neither of these can be compared in their revolutionary power to such things as speech and writing and agriculture.
[F] These were, at first, only those in which nature fertilized the soil after each harvest. Agriculture met with violent resistance from the pastoral nomads, but the agricultural way of life prevailed in the end because of the physical comforts it provided.
[G] But industry was a step in human progress to which subsequently there was nothing comparable until our own machine age.

苍蝇能传播出血热、细菌性痢疾等疾病。