职称英语考试理工类的AB级阅读理解(5)

　　The Compass 　　The great sea voyages of Europes Age of Discovery, such as Christopher Columbuss 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. 　　The jade connection is important. Lodestone is a hard materialthough 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. 　　31 What is the first paragraph mainly about? 　　B The compass was invented by Columbus. 　　D Columbus introduced the compass to the West Indies.