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 vaguest of insights. It is impossible to know today just what our Stone Age ancestors knew about plants, but form what we can observe of pre- industrial societies that still exist a detailed learning of plants and their properties must be extremely ancient. This is logical. Plants are the basis of the food pyramid for all living things even for other plants.
They have always been enormously important to the welfare of people not only for food, but also for clothing, weapons, tools, dyes, medicines, shelter, and a great many other purposes. Tribes living today in the jungles of the Amazon recognize literally hundreds of plants and know many properties of each. To them, botany, as such, has no name and is probably not even recognized as a special branch of knowledge at all.
Unfortunately, the more industrialized we become the farther away we move from direct contact with plants, and the less distinct our knowledge of botany grows. Yet everyone comes unconsciously on an amazing amount of botanical knowledge, and few people will fail to recognize a rose, an apple, or an orchid. When our Neolithic ancestors, living in the Middle East about 10,000 years ago, discovered that certain grasses could be harvested and their seeds planted for richer yields the next season the first great step in a new association of plants and humans was taken.
Grains were discovered and from them flowed the marvel of agriculture: cultivated crops. From then on, humans would increasingly take their living from the controlled production of a few plants, rather than getting a little here and a little there from many varieties that grew wild- and the accumulated knowledge of tens of thousands of years of experience and intimacy with plants in the wild would begin to fade away.
现在完成进行时的用法
将来完成时用法解说
过去将来完成时的用法
过去完成时的用法提醒
现在完成进行时与现在完成时的区别
时态详解:现在进行时
时态详解:一般过去时
时态详解:过去将来时
过去进行时的用法小结
两种完成进行时的用法
这个forget的时态要小心
表示将来的五种常用非时态方式
时间或条件状语从句不能用将来时态
英语基础语法:现在进行时
ago习惯上不与现在完成时连用
英语基础语法:过去将来时
英语基础语法:过去完成时
静态动词用于进行时态的例子
现在进行时用法小结
瞬间动词进行时的用法与意义
时态详解:一般将来时
过去完成时与一般过去时的区别
一般将来时用法小结
现在进行时用法详解
英语基础语法:现在完成时
这是根据语境确定时态的一道妙题
时态详解:过去完成时
时态详解:现在完成进行时
英语基础语法:过去进行时
过去完成时用法小结
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