Question: when did they start building the sydney opera house
[{'answer': 'March 1959', 'provenance': [{'wikipedia_id': '28222', 'title': 'Sydney Opera House', 'start_paragraph_id': 31, 'start_character': 127, 'end_paragraph_id': 31, 'end_character': 137, 'bleu_score': 1.0, 'section': 'Section::::Construction history.:Design and construction.\n'}]}, {'provenance': [{'wikipedia_id': '28222', 'title': 'Sydney Opera House', 'start_paragraph_id': 31, 'start_character': 0, 'end_paragraph_id': 31, 'end_character': 342, 'bleu_score': 0.7827314506328381, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11778067448680859062}, 'section': 'Section::::Construction history.:Design and construction.\n'}]}]