YOU SAID:
I LOVE my sister and brother and cat
INTO JAPANESE
私は私の姉と兄と猫が大好きです
BACK INTO ENGLISH
I love my sister, my brother and my cat
INTO JAPANESE
私は私の姉、私の兄、そして私の猫が大好きです
BACK INTO ENGLISH
I love my sister, my brother, and my cat
INTO JAPANESE
私は私の妹、私の兄弟、そして私の猫が大好きです
BACK INTO ENGLISH
I love my sister, my brother, and my cat
That didn't even make that much sense in English.