Science

Timing shifts by 22 years

作者：THE WASHINGTON POST

Through analysis of old tree rings reflecting the sun's history, scientists are setting a new timetable for what was happening in the dawning years of human history.The shift in timing seems sm...

点击阅读全文

对本期电子报订户、有效期内的VIP教师会员和本学期二十一世纪英文报尊享卡用户，我们开放所有内容：
如果您拥有以上权限，请点这里登录；
订阅电子报，请点这里；
激活VIP教师卡，请点这里；
激活21英语尊享卡，请点这里。