YOU SAID:
The dog and the cat were friends
INTO JAPANESE
犬と猫は友達だった
BACK INTO ENGLISH
The dog and the cat were friends.
INTO JAPANESE
犬と猫は友達でした。
BACK INTO ENGLISH
Dogs and cats were friends.
INTO JAPANESE
犬と猫は友達でした。
BACK INTO ENGLISH
Dogs and cats were friends.
That didn't even make that much sense in English.