百川归海
Follow the river and you'll get to the sea.
The sea refuses no river.
All rivers do what they can for the sea.
All roads lead to Rome.

eg：To find the cause is easy as you follow the river and you'll get to the sea.

中英俚语俗语来源：淮南子·论训"百川异源，而皆归于海。 "

同义词：殊途同归 There are more ways to the wood than one.