A country can be constituted-of-or-filled-with hills.Logical formLearned from17 sentences. A hill may lead.Logical formLearned from17 sentences. A ravine may be surrounded by hills.Logical formLearned from17 sentences. (Ski jump) may qualify on a hill.Logical formLearned from17 sentences. Hills can be difficult.Logical formLearned from17 sentences. Hundreds may fle into hills.Logical formLearned from17 sentences. A ski can be on a hill.Logical formLearned from17 sentences. A hill can be challenging.Logical formLearned from17 sentences. A fortress can be on a hill.Logical formLearned from17 sentences. A city may be built on a hill.Logical formLearned from16 sentences. A hill can be a hill.Logical formLearned from16 sentences. A valley can be between hills.Logical formLearned from16 sentences. Hills can be cold.Logical formLearned from16 sentences. A face may pertain-to hills.Logical formLearned from16 sentences. Hills may pertain-to a park.Logical formLearned from16 sentences.