Answer:
What does everyone know how to open but not how to close?
Walk on the living, they don't even mumble. Walk on the dead, they mutter and grumble.
Thirty white horses on a red hill, First they champ, Then they stamp, Then they stand still.
I drive men mad for love of me. Easily beaten, never free.
What do you throw out to use and take in when you're done?
I met a man on the London bridge, he tipped his hat and drew his name, in this riddle I told you his name. What is it?