Young Isaac Newton was 1 under a tree in the garden. There were many apples 2 the tree. Then suddenly(突然) something happened to wake him up. 3 apple fell(落下) on his head. He sat up and picked up the apple. He looked at the apple 4. "Why did the apple fall(落) down?" he asked 5, "Why didn't it fall up? Does a thing always fall down?" "Maybe there is something like gravity(引力), it 6 people on the ground. It pulls 7 towards the earth," he 8. Isaac Newton became a great 9 when he grew up. We are still learning 10 him now.