Airlines may operate flights.Logical formLearned from58 sentences. A group may operate in a world-city.Logical formLearned from58 sentences. A system of discounts may operate.Logical formLearned from58 sentences. An airline may operate a fleet of some aircraft.Logical formLearned from58 sentences. Companies may operate in a continent.Logical formLearned from58 sentences. A US-president may operate.Logical formLearned from58 sentences. Forces may operate in a country.Logical formLearned from58 sentences. Groups may operate in a region.Logical formLearned from58 sentences. Flights may operate at an airport.Logical formLearned from57 sentences. A chain may operate some stores.Logical formLearned from57 sentences. Some airlines may operate.Logical formLearned from57 sentences. Routes may be operated by a company.Logical formLearned from57 sentences. A mind may operate.Logical formLearned from57 sentences. Gangs may operate.Logical formLearned from57 sentences. Groups may operate in a country.Logical formLearned from56 sentences.