Re: tour operator vs travel agency
Your #1 a few posts ago -- the bus (coach) with their name on the side, an employee on the bus telling us about the sites, the meals paid for through the tour at pre-arranged restaurants, the hotels arranged, etc. -- that's what a tour operator is to me.
I might use my travel agent to book a tour with R2D2 tours, and my travel agent to get me the airline tickets to get to the start of the tour site, but then R2D2 takes over from there and makes sure I see everything there is to see.
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.