第4部分：阅读理解（第31～45题，每题3分，共45分）
下面有3篇短文，每篇幅短文后有5道题，每题材后面有4个选项。请仔细阅读短文并根据短文回答其后面的问题，从4个选项中选择一个最佳答案涂在答题卡相应的位置上。
The Compass
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 A.D. 80. 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 material——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.
