A
The great sea voyages of Europe's “Age of Discovery”， such as Christopher Columbus's trip to the West Indies in 1492, would have been impossible without the use of a compass.This great device for sea voyages was introduced to the West from China during the thirteenth century A．D.We have to thank ancient Chinese for their invention of the compass.
Two thousand years ago the Chinese had already developed a working compass.A piece of lodestone(天然磁石) would be cut into the shape of a ladle(长柄勺)．Placed on a stone board with a smooth surface, the lodestone would move round until the “handle” of the ladle pointed south while the bulk(主体) of the ladle was attracted to magnetic north.This interestingly shaped device is mentioned in a book from about 80 A．D.Other ancient books may have dated it as far back as the fourth century B．C.Jade(玉石) finders played an important role in the invention of the “ladle”．They travelled great distances to look for jade.In order not to lose directions, they would take a “ladle” with them.
The jade connection is important.Lodestone is a hard materia—though not as hard as some jade.And the making of a magnetic “ladle”， as well as a highly smooth stone board, would have required great skill.This suggests that the compass was invented by the jade finders of ancient China.
However, the making of a “ladle” was a tough job.Much work needed to shape a piece of lodestone into a ladle would mean much of its natural magnetism(磁性) had been lost.This again meant that only a few “ladles” could have been produced.Small numbers of ladles produced and growing need for navigation led to a search for ways to produce more compasses, and at the same time, smaller and better compasses.
语篇导读
本文为说明文，介绍了判别方位的简单仪器——司南。
21．When did ancient Chinese invent the compass?
A．In 1492.
B．In the thirteenth century A．D.
C．In 80 A．D.
D．At least 2,000 years ago.
解析 D 细节理解题。根据第二段第一句可知，2000年前，中国人就已经发明了可行的司南，故选D项。
22．What can we know about the ladleshaped compass?
A．The “handle” of the ladle pointed south.
B．The “handle” of the ladle pointed north.
C．The bulk of the ladle was attracted to south.
D．The bulk of the ladle remained unmoved on the board.
解析 A 细节理解题。根据第二段第三句可知，勺柄指向南方，故选A项。
23．What would the paragraph following this passage most probably discuss?
A．Various uses of ladleshaped compasses.
B．Improvement on the ladleshaped compasses.
C．Compasses introduced to the West from China.
D．The sea voyages of Europe's “Age of Discovery”．
解析 B 推理判断题。第四段中提到了司南在加工时容易失磁，只能制造出少量的司南，而航海的发展又需要更多携带方便和高质量的司南，因此下文可能会讲到勺形司南的改进，故选B项。
