SDcamps•演辩营全国英语演讲与辩论赛
Bacteria Bacteria are extremely small living things. While we measure our own sizes in inches or centimeters, bacterial size is measured in microns. One micron is a thousandth of a millimeter: a pinhead is about a millimeter across. Rod-shaped bacteria are usually from two to four microns long, while rounded ones are generally one micron in diameter. Thus if you enlarged a r...
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 considered quite seriously by many nations, especially since scientists have warned that the human race will outgrow its fresh wate...
British Columbia British Columbia is the third largest Canadian provinces, both in area and population. It is nearly 1.5 times as large as Texas, and extends 800 miles(1,280km) north from the United States border. It includes Canada’s entire west coast and the islands just off the coast. Most of British Columbia is mountainous, with long rugged ranges running north an...
The Nobel Academy For the last 82years, Sweden’s Nobel Academy has decided who will receive the Nobel Prize in Literature, thereby determining who will be elevated from the great and the near great to the immortal. But today the Academy is coming under heavy criticism both from the without and from within. Critics contend that the selection of the winners often has les...
Ford Although Henry Ford’s name is closely associated with the concept of mass production, he should receive equal credit for introducing labor practices as early as 1913 that would be considered advanced even by today’s standards. Safety measures were improved, and the work day was reduced to eight hours, compared with the ten-or twelve-hour day common at the ti...
American Revolution The American Revolution was not a sudden and violent overturning of the political and social framework, such as later occurred in France and Russia, when both were already independent nations. Significant changes were ushered in, but they were not breathtaking. What happened was accelerated evolution rather than outright revolution. During the conflict i...
Plankton浮游生物. Scattered through the seas of the world are billions of tons of small plants and animals called plankton. Most of these plants and animals are too small for the human eye to see. They drift about lazily with the currents, providing a basic food for many larger animals. Plankton has been described as the equivalent of the grasses that grow on the dry land co...
Lesson 7:Andrew Carnegie Andrew Carnegie, known as the King of Steel, built the steel industry in the United States, and , in the process, became one of the wealthiest men in America. His success resulted in part from his ability to sell the product and in part from his policy of expanding during periods of economic decline, when most of his competitors were reducing their i...
Collectibles Collectibles have been a part of almost every culture since ancient times. Whereas some objects have been collected for their usefulness, others have been selected for their aesthetic beauty alone. In the United States, the kinds of collectibles currently popular range from traditional objects such as stamps, coins, rare books, and art to more recent items of i...
Lesson 3:The Definition of “Price” Prices determine how resources are to be used. They are also the means by which products and services that are in limited supply are rationed among buyers. The price system of the United States is a complex network composed of the prices of all the products bought and sold in the economy as well as those of a myriad of services,...
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 sleep, dreaming and dreamless, depend on the life-style of the animal, and that predators are statistically much more likely to dre...
Topaz Topaz is a hard, transparent mineral. It is a compound of aluminum, silica, and fluorine. Gem topaz is valuable. Jewelers call this variety of the stone “precious topaz”. The best-known precious topaz gems range in color from rich yellow to light brown or pinkish red. Topaz is one of the hardest gem minerals. In the mineral table of hardness, it has a rati...
The origin of Refrigerators By the mid-nineteenth century, the term “icebox” had entered the American language, but ice was still only beginning to affect the diet of ordinary citizens in the United States. The ice trade grew with the growth of cities. Ice was used in hotels, taverns, and hospitals, and by some forward-looking city dealers in fresh meat, fresh fi...
Icebergs Icebergs are among nature’s most spectacular creations, and yet most people have never seen one. A vague air of mystery envelops them. They come into being —– somewhere ——in faraway, frigid waters, amid thunderous noise and splashing turbulence, which in most cases no one hears or sees. They exist only a short time and then slowly wast...
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 in the same litter, both brown and black furred bears may be born. Black bears are the smallest of all American bears, ranging in l...
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 a higher chance of being preserved than did terrestrial creatures because, as marine animals, they tended to live in environments l...
英语精美散文欣赏:Beauty 相关专题: 精美英文欣赏 美丽英文诵读 NSDA“SDcamps”全国英语演讲与辩论大赛（大学组）/SDcamps全国中小学生英语演讲与辩论大会（中小学及幼儿组）/美式辩论赛（以下简称大赛/大会）现诚招全国省市合作伙伴或城市合伙人，共同进行推广NSDA赛事品牌、举办赛事及培训活动、开展素质教育、美式营地项目等多方面合作。 我们希望认同NSDA理念，有赛事组织经验，或有教育资源，特别是有...
英语精美散文欣赏:All I Ever Readlly Needed to Know I Learned in Kinderqarten 相关专题: 精美英文欣赏 美丽英文诵读 NSDA“SDcamps”全国英语演讲与辩论大赛（大学组）/SDcamps全国中小学生英语演讲与辩论大会（中小学及幼儿组）/美式辩论赛（以下简称大赛/大会）现诚招全国省市合作伙伴或城市合伙人，共同进行推广NSDA赛事品牌、举办赛事及培训活动、开展素质教育、美式营地项目等多方面合作。 我们希...
The life I desired 我所追求的生活 That must be the story of innumerable couples,and the pattern of lifeof life it offers has a homely grace.It reminds you of a placid rivulet,meandering smoohtly through green pastures and shaded by pleasant trees,till at last it falls into the vasty sea;but the sea is so calm,so silent,so infifferent,that you are troubled suddently by a vagu...
Three passions, simple but overwhelmingly strong, have governed my life: the longing for love, the search for knowledge, and unbearable pity for the suffering of mankind. These passions, like great winds, have blown me hither and thither, in a wayward course, over a great ocean of anguish, reaching to the very verge of despair. I have sought love, first, because it brings ec...