You stay alone and you are sleeping in your room when your friends are ringing the doorbell. They've come to have breakfast with you and all you have at home is a box of cornflakes, Bread, Jam and one carton of Milk. What will you open first?
Door? Nah.. You first need to open your eyes!
Một tá chiếc móc khóa gồm bao nhiêu chiếc chìa khóa?
Chỉ có móc thì không có chìa