There are about 98% thick continentalicesheet 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 continentalsheet 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 continentalice-sheet covering Canada on the other.