“仍有情况处于未知状态，”他说，“我们不知道它的面积有多大？

"There is still a lot we don't know, " he said.

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说，有一点，等到人类祖先出现时，欧亚大陆的大片地区还处在未知状态，或者只有部分经过努力的先驱者才知道。

For one thing, Slimak said, when it comes to human ancestral species, "large parts of Eurasia remain largely unknown, or known only by the efforts of some pioneering researchers."

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