The Moon's Origin   One of the earliest scientific theories about the Moon's origin postulated that Earth and its moon formed out of a dust cloud alongside one another, much a...

Animal Farming in the Chesapeake Colonies The Chesapeake colonies were established by English settlers near Chesapeake Bay in North America in the seventeenth century. Tobacco pr...

Sources of Prosperity during China's Song Dynasty     In the tenth century. after a period of political fragmentation, China began to enjoy a peaceful and prosperous per...

The Key Factors Influencing Soil Formation   Soil is the product of the complex interplay of several factors. Weathering, a process that breaks down rocks by physical (mechani...

Dutch Art and the Middle Class     Throughout history,the wealthy have been the most avid art collectors. Indeed, the money necessary to commission leading artists to ...

The History and Composition of Laundry Detergent     The earliest ancient people used plain water for cleaning. Water can dissolve different kinds of substances and then...

  Sunspot Cycles   Dark regions on the Sun, called sunspots, were studied in 1610 by Galileo, who turned the newly invented telescope on objects in the sky. A lively deba...

Classical Greek Tragedy       In 534 B.c.E. the city-state of Athens in what is today Greece added performances of tragedies to its annual festival honoring the go...

Human Responsibility for Megafaunal Extinctions     Paleontologists are intrigued by the question of what caused a diverse group of large animals (megafauna) to become e...

TF阅读真题第848篇Wool production in Europe on the high Middle Ages