题目选项分析

Between 14,000 and 8,000 B.C. the ice cap that covered northern Asia, Europe, and America began to melt, uncovering vast new areas that were to be occupied by migrating peoples moving northward.

Between 14,000 and 8,000 B.C. the ice cap that covered northern Asia, Europe, and America began, after melting, uncovering vast new areas which are to be occupied by migrating peoples moving northward.