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By Jessica Berman Washington 31 May 2007 Scientists say early human ancestors may have begun walking on two legs on tree branches, not on the ground as commonly believed. The evidence contradicts the long-held belief that early humans first began wal
发表于:2018-12-08 / 阅读(98) / 评论(0)
2007年VOA标准英语（五月）
2007年VOA标准英语（五月）