A (security apparatus) can be effective in preventing (terror attacks).Logical formLearned from15 sentences. Roadblocks may prevent a deal.Logical formLearned from15 sentences. Weather may prevent an (emergency flight) to a hospital.Logical formLearned from15 sentences. Weather may prevent helicopters from flying.Logical formLearned from15 sentences. Reporters may be prevented from reaching an area.Logical formLearned from15 sentences. Communications may prevent authorities from issuing (damage estimates).Logical formLearned from15 sentences. Implants may prevent a head from fall_offing shoulders.Logical formLearned from15 sentences. Part can be in preventing irregularities.Logical formLearned from15 sentences. Violence may prevent a fair election.Logical formLearned from15 sentences. Scenes may prevent results.Logical formLearned from15 sentences. Health may prevent a male.Logical formLearned from15 sentences. Injury may prevent a male.Logical formLearned from14 sentences. A death may be prevented.Logical formLearned from14 sentences. A container may prevent leakage.Logical formLearned from14 sentences. Persons may prevent a male.Logical formLearned from14 sentences.