Passage Four
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 from what we can observe of preindustrial 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 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 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.
16. Which of the following assumptions about early humans is expressed in the passage？
A. They divided knowledge into several fields.
B. They probably had extensive knowledge of plants.
C. They knew little about the environment they were living in.
D. They invented the term“botany”but had no idea of what it was about.
17. The phrase“properties of each”in paragraph 1 refers to the properties of .
A. each tribe B. each jungle
C. each plant D. each purpose
18. The author mentions“a rose，an apple，or an orchid”in paragraph 2 to .
A. make the passage more poetic
B. test the reader’s knowledge
C. illustrate the diversity of botanical life
D. give botanical examples that most readers will recognize
19. According to the passage，why has general knowledge of botany declined？
A. Industrialization has spoiled the natural environment.
B. Botany is no longer regarded as a special branch of science.
C. Research is unable to keep up with the increasing number of plants.
D. Direct contact with a variety of plants has decreased.
20. According to the passage，what was the first great step taken toward agriculture？
A. The invention of agricultural machinery.
B. The production of a controlled number of plants.
C. The discovery of certain grasses that could be harvested and replanted.
D. The close relationship between human beings and plants.

参考答案：16-20 BCDDC