| 1. | The force of gravity pulls things towards the earth 's center .
地心吸力把物体吸向地心。 |
| 2. | The force of gravity pulls things towards the earth ' s centre
地心吸力把物体吸向地心 |
| 3. | Book number was " the secrets of gravitation !
书名是《地心吸力的奥秘》 。 |
| 4. | Sports is a kind of genetics . it s a challenge to gravity
运动是一种科学，是对地心吸力的挑战！ |
| 5. | If the earth had no gravity , the moon would fly to the sun
如果地球没有地心吸力，月亮可能飞向太阳！ |
| 6. | It s said that there s another story about how newton discovered gravity
牛顿发现地心吸力的故事背后，传说还有段故事！ |
| 7. | It s said that besides apples , newton also used vegetables to study gravity
传说除了苹果外，牛顿还用蔬菜来研究地心吸力！ |
| 8. | It s said that besides apples , newton also used vegetables to study gravity
传说除了苹果外，牛顿还用蔬菜来研究地心吸力！ |
| 9. | It s said that once the apple fell , newton began seriously studying gravity
传说自从那个苹果掉下来后，牛顿便开始努力研究地心吸力 |
| 10. | It s said that once the apple fell , newton began seriously studying gravity
传说自从那个苹果掉下来后，牛顿便开始努力研究地心吸力 |
