Sentence 1: I dropped out of college and decided to join the Marine Corps. 
 Sentence 3: Boot camp was hard and the drill instructors yelled at us constantly 
 Sentence 4:  The experience challenged me both mentally and physically 
 Sentence 5:  At the end of boot camp I was proud to have become a Marine 
 Option 1: I got and failed a medical checkup and wasn't allowed to go to boot camp. 
 Option 2: I got a medical checkup and was then ready to go to boot camp.