Answer:
I go through a door but never go in, and never come out. What am I?
I am alive without breath and cold as death. I am never thirsty but always drinking.
I mean goodbye for South Americans.
What is made of wood, but can't be sawed?
Tear me off and scratch my head, what once was red is black instead. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.