职称英语理工类C级阅读理解题必备练习(1)

　　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.