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1·There are about 98% thick continental ice sheet and 2% barren rock.

南极约98%覆盖着厚厚的大陆冰床，2%光秃的岩石。

2·The continental sheet sent out a vast – and final – armada of floating ice, which covered much of the northern seas.

最后，一个巨大浮冰脱离了大陆，它覆盖了大部分的北部海域。

3·The way further south into the rest of America was through an ice-free corridor between the Rocky Mountains on the Pacific side, and the vast continental ice-sheet covering Canada on the other.

当年一道巨大的无冰走廊，一头向着通过太平洋一侧的洛基山脉一路向南延伸至美国各地，另一头深深延伸至被大陆冰层覆盖着的加拿大广袤土地。