引力

例句：

1. 1. The earth's gravity pulls the moon towards it.
   地球的重力将月亮拉向地球。
2. 2.The weight of the book is too heavyfor me to carry.
   这本书的重量对我来说太重，我搬不动。
3. 3. The intensity of thestorm was so strong that it knocked downtrees and power lines.
   暴风雨的强度如此之大，以至于它把树木和电线都吹倒了。