Some (gas stations) can be in a world-city.Logical formLearned from21 sentences. Gas may undergo an inhalation.Logical formLearned from21 sentences. A bulk may pertain-to a natural gas.Logical formLearned from21 sentences. Persons may pump gas.Logical formLearned from21 sentences. Gas can be turbulent.Logical formLearned from21 sentences. Exploration can be for gas.Logical formLearned from21 sentences. Gas can be secret.Logical formLearned from21 sentences. Gas may undergo eruptions.Logical formLearned from21 sentences. (Gas exchange) may occur.Logical formLearned from21 sentences. Gas can be irritating.Logical formLearned from21 sentences. Levels can be constituted-of-or-filled-with natural gas.Logical formLearned from21 sentences. A contract can be for natural gas.Logical formLearned from21 sentences. Gas may undergo explosions.Logical formLearned from21 sentences. A person may pass some (gas stations).Logical formLearned from21 sentences. Persons may get gas.Logical formLearned from21 sentences.