Re: usage of 'complement'
I was the public affairs officer for a naval aviation station, and then was the operations officer for a joint-service unit that processed people entering all branches of the service. The first job was more fun. (However, I spent four weeks on ships during each of the summers after my freshman year of college and my junior year of college.)
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.