YOU SAID:

The dog has gotten lost.

INTO JAPANESE

犬は失われてしまった。

BACK INTO ENGLISH

The dog has been lost.

INTO JAPANESE

犬が失われました。

BACK INTO ENGLISH

Lost dog.

INTO JAPANESE

失われた犬。

BACK INTO ENGLISH

A lost dog.

INTO JAPANESE

失われた犬。

BACK INTO ENGLISH

A lost dog.