Apache 2 in ubuntu eC2 aws does not want to start or reload or stop

I can't restart apache2 for some reason ,,,I know is an easy fix but I can't find the problem.....This server in AWS ec2 and I was setting up vhosts when it failed to restart This probably would take somebody that know 5 minutes or less to find out ......but I need not only to fix it but the information on what was wrong with it because I'm going to school and I'm learning this and need to know.... I need somebody to tell me exactly how they fixed and explained what happened...