YOU SAID:
i am at home and my sister is cooking
INTO JAPANESE
私は家にいて、妹は料理をしています
BACK INTO ENGLISH
I'm at home and my sister is cooking.
INTO JAPANESE
私は家にいて、妹は料理をしています。
BACK INTO ENGLISH
I'm at home and my sister is cooking.
That didn't even make that much sense in English.