She didn't want to fall down like other leaves.
她不想像其他树叶一样落下。
She saw the leaves fall down.
她看到树叶飘落。
Lan said if her house could fly, it wouldn't fall down in an earthquake.
兰说,如果她的房子能飞,就不会在地震中倒塌。
Why did it fall down?
它为什么掉了下来？
It can improve your balance by exercising your main muscles so that you can't fall down.
它可以通过锻炼你的`主要肌肉来改善你的平衡感，这样你就不会摔倒。