HOW LIFE BEGAN ON THE EARTH地球上生命的起源 No one knows exactly how the earth began, as it happened so long ago. However, according to a widely accepted theory, the universe began with a Big Bang that threw matter in all directions.After that, atoms began to form and combine to create stars and other bodies.没有人确切知道地球是怎么样开始形成的，因为在很早很在以前地球就形成了。然而，一种普遍为人们所接受的理论是：宇宙起源于一次大爆炸，这次大爆炸将物质投射到四面八方。然后，原子开始形成并结合成恒星和其他天体。For several billion years after the Big Bang, the earth was still just a cloud o
