YOU SAID:
The dog had had ten previous owners
INTO JAPANESE
犬の飼い主は10人いた
BACK INTO ENGLISH
There were ten dog owners
INTO JAPANESE
犬の飼い主は10人いました
BACK INTO ENGLISH
There were 10 dog owners
INTO JAPANESE
犬の飼い主は10人いました
BACK INTO ENGLISH
There were 10 dog owners
You should move to Japan!