YOU SAID:

Frogs in a well know nothing of the sea

INTO JAPANESE

井戸の中のカエルは海のことを何も知らない

BACK INTO ENGLISH

The frog in the well knows nothing about the sea.

INTO JAPANESE

井の中の蛙は海のことを何も知りません。

BACK INTO ENGLISH

The frog in the well knows nothing about the sea.