标签：优美 相关文章
14 A Rare Fossil Record The preservation of embryos and juveniles is a rate occurrence in the fossil record. The tiny, delicate skeletons are usually scattered by scavengers or destroyed by weathering before they can be fossilized. Ichthyosaurs had
新概念优美背诵短文50篇
17.Evolution of sleep Sleep is very ancient. In the electroencephalographic sense we share it with all the primates and almost all the other mammals and birds: it may extend back as far as the reptiles. There is some evidence that the two types of s
新概念优美背诵短文50篇
42.Coal-fired power plants The invention of the incandescent light bulb by Thomas A. Edison in 1879 created a demand for a cheap, readily available fuel with which to generate large amounts of electric power. Coal seemed to fit the bill, and it fuel
新概念优美背诵短文50篇
41.American black bears American black bears appear in a variety of colors despite their name. In the eastern part of their range, most of these brown, red, or even yellow coats. To the north, the black bear is actually gray or white in color. Even
新概念优美背诵短文50篇
40 Cohesion-tension Theory Atmospheric pressure can support a column of water up to 10 meters high. But plants can move water much higher; the sequoia tree can pump water to its very top more than 100 meters above the ground. Until the end of the ni
新概念优美背诵短文50篇
45.The source of Energy A summary of the physical and chemical nature of life must begin, not on the Earth, but in the Sun; in fact, at the Suns very center. It is here that is to be found the source of the energy that the Sun constantly pours out i
新概念优美背诵短文50篇
44.Obtaining Fresh water from icebergs The concept of obtaining fresh water from icebergs that are towed to populated areas and arid regions of the world was once treated as a joke more appropriate to cartoons than real life. But now it is being con
新概念优美背诵短文50篇
18.Modern American Universities Before the 1850s, the United States had a number of small colleges, most of them dating from colonial days. They were small, church connected institutions whose primary concern was to shape the moral character of thei
新概念优美背诵短文50篇
26. International Business and Cross-cultural Communication The increase in international business and in foreign investment has created a need for executives with knowledge of foreign languages and skills in cross-cultural communication. Americans,
新概念优美背诵短文50篇