Âm thanh chia sẻ

How a Door Works A door is simple, but it must work well. The door is attached to the frame with hinges. Hinges allow the door to swing open and closed. A handle lets you pull or push the door. A lock keeps the door closed for security. The door must fit perfectly in the frame. If there is a big gap, air and noise will come in. If it fits too tight, it will be hard to open.  Carpenter: "A small gap is fine. It needs room to open without rubbing."   Worker: "Okay. After the hinges, we pu