A line of showers may prevent a world-city from returning to a (home base).Logical formLearned from6 sentences. International treaty may prevent victims of a crash.Logical formLearned from6 sentences. A part can be in preventing attacks.Logical formLearned from6 sentences. Sanctions may prevent officials from traveling.Logical formLearned from6 sentences. A blockade may be aimed at preventing access to islands.Logical formLearned from6 sentences. A country may prevent a conflict with guerrillas.Logical formLearned from6 sentences. A legislature may prevent drilling.Logical formLearned from6 sentences. A measure may prevent members of a public from viewing photos.Logical formLearned from6 sentences. A knee may prevent a female from keep_upping with a rest of a team.Logical formLearned from6 sentences. A move may prevent disasters.Logical formLearned from6 sentences. Differences may prevent agreement.Logical formLearned from6 sentences. Persons may prevent cases.Logical formLearned from6 sentences. Gunfire may prevent firefighters from reaching an area.Logical formLearned from6 sentences. A storm may prevent helicopters from flying.Logical formLearned from6 sentences. Wind may prevent a touchdown.Logical formLearned from6 sentences.