Watch LaterAdded 03:38 政府解密 What you might not know about the Declaration of Independence – Kenneth C. Davis
Watch LaterAdded 05:12 事物科學 What’s the difference between a scientific law and theory? – Matt Anticole
Watch LaterAdded 05:01 神奇自然 When will the next mass extinction occur? – Borths, D’Emic, and Pritchard