单项选择题

According to the passage, what was the first great step toward the practice of agriculture

A．The invention of agricultural implements and machinery .
B．The development of a system of names for plants.
C．The discovery of grasses that could be harvested and replanted.
D．The changing diets of early humans.

<上一题目录下一题>

热门试题

单项选择题

What does the comment This is logical (Line 5) mean

A．There is no clear way to determine the extent of our ancestors' knowledge of-plants.
B．It is not surprising that early humans had a detailed knowledge of plants.
C．it is reasonable to assume that our ancestors behaved very much like people in pre-industrial societies.
D．Human knowledge of plants is well organized and very detailed.

单项选择题

According to the passage, why has general knowledge of botany begun to fade

A．People no longer value plants as a useful resource.
B．Botany is not recognized as a special branch of science.
C．Research is unable to keep up with increasing numbers of plants.
D．Direct contact with a variety of plants has decreased.