An obstacle can be unfortunate.Logical formLearned from7 sentences. An obstacle can be in a development of relations.Logical formLearned from7 sentences. Obstacles can be wooden.Logical formLearned from7 sentences. A line can be constituted-of-or-filled-with obstacles.Logical formLearned from7 sentences. An obstacle can be to an advance.Logical formLearned from7 sentences. An obstacle can be formidable.Logical formLearned from7 sentences. An obstacle can be to a (peace treaty).Logical formLearned from7 sentences. An obstacle can be ideological.Logical formLearned from7 sentences. An obstacle can be to deployment.Logical formLearned from7 sentences. A case can be an obstacle.Logical formLearned from7 sentences. A river can be an obstacle.Logical formLearned from7 sentences. Obstacles can be on a trail.Logical formLearned from7 sentences. An obstacle can be in a us-state.Logical formLearned from7 sentences. Obstacles can be for development.Logical formLearned from7 sentences. Obstacles can be in a continent.Logical formLearned from7 sentences.