ebb and flow

• 兴衰； 起伏

ebb and flow的用法和样例：

例句

1. Throughout history empires have waxed and waned.
   历史上各个帝国革故鼎新均有兴衰。
2. I am reading a book about the rise and fall of the Roman Empire.
   我正在看一本关于罗马帝国兴衰的书。
3. The ship pitched and tossed in the rough seas.
   轮船在汹涌澎湃的大海中起伏颠簸。
4. And the tempo of the sea speeded up.
   同时大海的起伏动荡加剧了。