YOU SAID:

Once upon a time, there lived a snail.

INTO JAPANESE

かつて、カタツムリが住んでいました。

BACK INTO ENGLISH

Once a snail lived.

INTO JAPANESE

一度カタツムリが住んでいた。

BACK INTO ENGLISH

Once the snail lived.

INTO JAPANESE

いったんカタツムリが住んでいた。

BACK INTO ENGLISH

Once the snail lived.