Question: the most common form of megalithic architecture in europe is
[{'answer': 'the portal tomb', 'provenance': [{'wikipedia_id': '332248', 'title': 'Megalith', 'start_paragraph_id': 12, 'start_character': 61, 'end_paragraph_id': 12, 'end_character': 76, 'bleu_score': 1.0, 'section': 'Section::::European megaliths.\n'}]}, {'answer': 'portal tomb', 'provenance': [{'wikipedia_id': '332248', 'title': 'Megalith', 'start_paragraph_id': 12, 'start_character': 65, 'end_paragraph_id': 12, 'end_character': 76, 'bleu_score': 1.0, 'section': 'Section::::European megaliths.\n'}]}, {'provenance': [{'wikipedia_id': '332248', 'title': 'Megalith', 'start_paragraph_id': 12, 'start_character': 4, 'end_paragraph_id': 12, 'end_character': 814, 'bleu_score': 0.8851101511307291, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6191329395893994295}, 'section': 'Section::::European megaliths.\n'}]}, {'provenance': [{'wikipedia_id': '332248', 'title': 'Megalith', 'section': 'Section::::European megaliths.\n', 'start_paragraph_id': 12, 'end_paragraph_id': 12, 'meta': {'evidence_span': ['The most common type of megalithic construction in Europe is the portal tomb a chamber consisting of upright stones (orthostats) with one or more large flat capstones forming a roof.', 'The most common type of megalithic construction in Europe is the portal tomb a chamber consisting of upright stones (orthostats) with one or more large flat capstones forming a roof.', 'The most common type of megalithic construction in Europe is the portal tomb a chamber consisting of upright stones (orthostats) with one or more large flat capstones forming a roof.']}}]}]