The Radiocarbon Dating of Prehistoric American Sites     Because all living things contain carbon, artifacts and organic remains from archaeological sites can often be d...

TF阅读真题第865篇The Origins of Life on Earth

TF阅读真题第897篇How Fossils Map the Past

官方评分规则 谈到分数评估，首先是需要明确PET考试评分规则。1、总分评分简单分析下B1 Preliminary（PET）的评分。PET的最终分数是阅读、写作、听力、口语四项的平均分（这点很类似雅思）。最...

Ocean and Atmosphere on Early Earth Where did Earth's ocean water come from? Scientists agree that a large amount of water must have arrived during planet, accretion, which is the ...

第61篇The Origins of Agriculture

第93篇The Agricultural Revolution

第125篇The Extinction of the Dinosaurs

第158篇Pleistocene Extinctions

第189篇Mass Production: Method and Impact