"Using” and “moving” were the key words when trying to figure out whether South Shore Iron Works was insured — under the $1 million auto policy GD Carriers purchased from National Casualty Co. — for an accident where Julio Delgado, a GD employee, fell from a parked flatbed trailer owned by South Shore.Delgado hooked GD’s tractor to South Shore’s trailer while it was being loaded with steel beams he was scheduled to transport to a project in Rochelle in north central Illinois …