Question: when did they start building the twin towers
[{'answer': 'August 1968', 'provenance': [{'wikipedia_id': '7777427', 'title': 'Construction of the World Trade Center', 'start_paragraph_id': 4, 'start_character': 62, 'end_paragraph_id': 4, 'end_character': 73, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '7777427', 'title': 'Construction of the World Trade Center', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 451, 'bleu_score': 0.8681942591026711, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7242420685473417181}, 'section': 'Section::::Abstract.'}]}]