A detention can be compulsory.Logical formLearned from31 sentences. An unit can be compulsory.Logical formLearned from31 sentences. A (sex education) can be compulsory.Logical formLearned from31 sentences. An insurance can be compulsory.Logical formLearned from30 sentences. An exercise can be compulsory.Logical formLearned from30 sentences. (Job losses) can be compulsory.Logical formLearned from30 sentences. A certification can be compulsory.Logical formLearned from29 sentences. An inspection can be compulsory.Logical formLearned from29 sentences. Dives can be compulsory.Logical formLearned from29 sentences. A (licensing scheme) can be compulsory.Logical formLearned from29 sentences. Activities can be compulsory.Logical formLearned from29 sentences. A course can be compulsory.Logical formLearned from29 sentences. Routines can be compulsory.Logical formLearned from29 sentences. A reporting can be compulsory.Logical formLearned from29 sentences. Studies can be compulsory.Logical formLearned from29 sentences.