Question: what natural boundary lies between thailand and laos
[{'answer': 'Myanmar', 'provenance': [{'wikipedia_id': '20388', 'title': 'Geography of Myanmar', 'start_paragraph_id': 0, 'start_character': 13, 'end_paragraph_id': 0, 'end_character': 20, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '20388', 'title': 'Geography of Myanmar', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 383, 'bleu_score': 0.8292714260728251, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15177877114388705168}, 'section': 'Section::::Abstract.'}]}]