Sailors long ago were often afraid that if they sailed too far from home they would fall off the __

题目

Sailors long ago were often afraid that if they sailed too far from home they would fall off the __
of the flat ocean.

答案

Sailors long ago were often afraid that if they sailed too far from home they would fall off the earth.严格的说这其实是个地理题：中世纪人们人为地球是一个盘子,扁平状,航行到边上就会掉下去——所以后来哥伦布环行地球一周引起了轰动