Supervisor who does not answer My advisor has not replied to my email for 4 days. I'm in a hurry, this is a piece of paper that he should sign for me before December 18 what to do? any exemple of emails ? please help!!!



Finally, I sent him an email with the subject "urgent" and it worked, he replied almost instantly.
Go see him. Failing that, go see the department office. They can intercede for you if he isn't responding. Actually four days isn't so much time in a busy season. And he may not realize your urgency. 

Email is not your friend here. Especially if your advisor is a generation or two older than you.