Blacks may be prevented.Logical formLearned from17 sentences. A (gag order) may prevent some students from presenting findings.Logical formLearned from17 sentences. A bulk of mail may prevent replies to a letter.Logical formLearned from17 sentences. A key can be to preventing.Logical formLearned from17 sentences. An injury may prevent a male.Logical formLearned from17 sentences. Factors can be in preventing accidents.Logical formLearned from17 sentences. Forces may be prevented from entering a town.Logical formLearned from17 sentences. (Security forces) may prevent (street demonstrations).Logical formLearned from17 sentences. A boycott of fraud may prevent voting from taking place.Logical formLearned from17 sentences. Security may prevent violence.Logical formLearned from17 sentences. (Security measures) may prevent attacks.Logical formLearned from17 sentences. An army may prevent monitors from reaching villages.Logical formLearned from17 sentences. Police may prevent journalists from getting closer.Logical formLearned from17 sentences. A French government can be intent on preventing bloodshed.Logical formLearned from17 sentences. Illness may prevent a male.Logical formLearned from16 sentences.