YOU SAID:
I ate her friend's dog
INTO JAPANESE
友達の犬を食べました
BACK INTO ENGLISH
Ate my friend's dog
INTO JAPANESE
友達の犬を食べた
BACK INTO ENGLISH
Ate a friend's dog
INTO JAPANESE
友達の犬を食べた
BACK INTO ENGLISH
Ate a friend's dog
That didn't even make that much sense in English.