In the late 1400s, when Christopher Columbus returned to Spain from the western part of the earth,he brought with him a sample of corn.(1)_______________________________________________.The corn that Columbus introduced to Europe was originally native to Mexico.The peoples of the Americans probably started to plant this grass as early as 5000 B.C.After about a thousand years, they had developed highly productive types of corn which later became the basis for the great pre-Columbian civilizations.Actually, many countries regarded corn as one of their basic crops.To certain degree, we can say that many ancient cities were built on corn.(2)____________________________________. The corn and the people who cultivated it developed together.Without humans to care for it, corn could not survive.There were times when some natural disasters stroke corn planting.The people who planted corn made great effort to protect it from being destroyed.They tried to gather the seeds to enlarge the planting areas.The planting people tried various ways to enhance the production of corn.(3)_____________________________________________.They also have to make sure corn is watered when there's a lack of rain.
corn has become a porpular and nutritious food of our daily diet
corn has become basic food of men and domestic animal ,such as chick and pig
they get rid of the weeds and fertilize the corn in regular time
发表于 2012-1-29 14:23
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发表于 2012-2-25 13:14
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