A person may challenge a male to a debate.Logical formLearned from7 sentences. Systems may be challenged.Logical formLearned from7 sentences. A team may challenge for a title.Logical formLearned from7 sentences. A law may be challenged.Logical formLearned from7 sentences. A male may challenge a candidate.Logical formLearned from7 sentences. Principles of expression may be challenged.Logical formLearned from7 sentences. A male may challenge for a championship.Logical formLearned from7 sentences. A study may be challenged.Logical formLearned from7 sentences. A finding may challenge a notion.Logical formLearned from7 sentences. Some law may be challenged.Logical formLearned from7 sentences. Models of nuclear structure may be challenged.Logical formLearned from7 sentences. Persons may challenge ideas.Logical formLearned from7 sentences. Constraints may challenge an ability.Logical formLearned from7 sentences. A consensus may be challenged.Logical formLearned from7 sentences. A person may challenge an advocate.Logical formLearned from7 sentences.