YOU SAID:
I have large bags of milk in my basement
INTO JAPANESE
私は私の地下室に大きな袋の袋を持っている
BACK INTO ENGLISH
I have a bag of big bags in my basement
INTO JAPANESE
私は私の地下に大きな袋の袋を持っています
BACK INTO ENGLISH
I have a bag of big bags in my basement
You've done this before, haven't you.