1-C. This system had developed over hundreds of years as a result of political and commercial situations.This system had developed over hundreds of years as a result of political and commercial situations.
2. Airline pilots fly passengers and cargo on long or short-haul flights for leisure, business or commercial purposes.Airline pilots fly passengers and cargo on long or short-haul flights for leisure, business or commercial purposes.
3. For example, consumers now use digital video recorders to time-shift shows and skip through commercial breaksFor example, consumers now use digital video recorders to time-shift shows and skip through commercial breaks