YOU SAID:
your mom is fatter than your sisters black dog
INTO JAPANESE
あなたのお母さんはあなたの姉妹の黒い犬より太っています
BACK INTO ENGLISH
Your mom is fatter than your sister's black dog
INTO JAPANESE
あなたのお母さんはあなたの妹の黒い犬より太っている
BACK INTO ENGLISH
Your mom is fatter than your sister's black dog
That didn't even make that much sense in English.