YOU SAID:
i like my sisters cat
INTO JAPANESE
私は私の姉妹猫が好きです
BACK INTO ENGLISH
I like my sister cat
INTO JAPANESE
私は妹の猫が好きです
BACK INTO ENGLISH
I like my sister's cat
INTO JAPANESE
妹の猫が好きです
BACK INTO ENGLISH
I like my sister's cat
Come on, you can do better than that.