新东方背诵文选 L31 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

新东方背诵文选 L32 Botany

Botany, the study of plants, occupies a peculiar position in the history of human knowledge. For many thousands of years it was the one field of awareness about which humans had anything more than the

新东方背诵文选 L39 The Salinity of Ocean Waters

If the salinity of ocean waters is analyzed, it is found to vary only slightly from place to place. Nevertheless, some of these small changes are important. There are three basic processes that cause

新东方背诵文选 L35.Oil Refining

An important new industry, oil refining, grew after the Civil war. Crude oil, or petroleum - a dark, thick ooze from the earth - had been known for hundreds of years, but little use had ever been made

新东方背诵文选 L38 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

新东方背诵文选 L33 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 lazi

新东方背诵文选 L40 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. U

新东方背诵文选 L34 Raising Oysters

In the oysters were raised in much the same way as dirt farmers raised tomatoes- by transplanting them. First, farmers selected the oyster bed, cleared the bottom of old shells and other debris, then

新东方背诵文选 L37 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 wat

新东方背诵文选 L30 The origin of Refrigerators

By the mid-nineteenth century, the term

新东方背诵文选 L24．Piano

The ancestry of the piano can be traced to the early keyboard instruments of the fifteenth and sixteenth centuries --- the spinet, the dulcimer, and the virginal. In the seventeenth century the organ,

新东方背诵文选 L25. Movie Music

Accustomed though we are to speaking of the films made before 1927 as

新东方背诵文选 L26. International Business and Cross-cultura

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, however,

新东方背诵文选 L29 Telecommuting

Telecommuting-- substituting the computer for the trip to the job ---- has been hailed as a solution to all kinds of problems related to office work. For workers it promises freedom from the office, l

新东方背诵文选 L28.Changing Roles of Public Education

One of the most important social developments that helped to make possible a shift in thinking about the role of public education was the effect of the baby boom of the 1950's and 1960's on the school

新东方背诵文选 L22. Collectibles

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新东方背诵文选 L19.children's numerical skills

people appear to born to compute. The numerical skills of children develop so early and so inexorably that it is easy to imagine an internal clock of mathematical maturity guiding their growth. Not lo

新东方背诵文选 L27. Scientific Theories

In science, a theory is a reasonable explanation of observed events that are related. A theory often involves an imaginary model that helps scientists picture the way an observed event could be produc

新东方背诵文选 L21 The Origin of Sports

When did sport begin? If sport is, in essence, play, the claim might be made that sport is much older than humankind, for , as we all have observed, the beasts play. Dogs and cats wrestle and play bal

新东方背诵文选 L17.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 evide