A basis can be voluntary.Logical formLearned from5 179 sentences. Contributions can be voluntary.Logical formLearned from2 938 sentences. A program can be voluntary.Logical formLearned from2 924 sentences. Participation can be voluntary.Logical formLearned from1 757 sentences. A recall can be voluntary.Logical formLearned from1 534 sentences. Guidelines can be voluntary.Logical formLearned from1 401 sentences. An agreement can be voluntary.Logical formLearned from1 380 sentences. A repatriation can be voluntary.Logical formLearned from1 308 sentences. Standards can be voluntary.Logical formLearned from1 135 sentences. Measures can be voluntary.Logical formLearned from1 127 sentences. A code can be voluntary.Logical formLearned from1 125 sentences. Programs can be voluntary.Logical formLearned from1 110 sentences. Efforts can be voluntary.Logical formLearned from1 031 sentences. A system can be voluntary.Logical formLearned from1 017 sentences. A service can be voluntary.Logical formLearned from1 010 sentences.