Question: when was the titanic started to be built
[{'answer': '31 March 1909', 'provenance': [{'wikipedia_id': '19285924', 'title': 'RMS Titanic', 'start_paragraph_id': 64, 'start_character': 153, 'end_paragraph_id': 64, 'end_character': 166, 'bleu_score': 1.0, 'section': 'Section::::Building and preparing the ship.:Construction, launch and fitting-out.\n'}]}, {'provenance': [{'wikipedia_id': '19285924', 'title': 'RMS Titanic', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3830040328034099408}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '19285924', 'title': 'RMS Titanic', 'start_paragraph_id': 64, 'start_character': 0, 'end_paragraph_id': 64, 'end_character': 648, 'bleu_score': 0.7566177413636611, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3830040328034099408}, 'section': 'Section::::Building and preparing the ship.:Construction, launch and fitting-out.\n'}]}, {'provenance': [{'wikipedia_id': '19285924', 'title': 'RMS Titanic', 'section': 'Section::::Building and preparing the ship.:Construction, launch and fitting-out.\n', 'start_paragraph_id': 64, 'end_paragraph_id': 64, 'meta': {'evidence_span': ['The construction of "Olympic" and "Titanic" took place virtually in parallel, with "Olympic"s keel laid down first on 16 December 1908 and "Titanic"s on 31 March 1909.', '"Titanic"s on 31 March 1909.', 'The construction of "Olympic" and "Titanic" took place virtually in parallel, with "Olympic"s keel laid down first on 16 December 1908 and "Titanic"s on 31 March 1909.']}}]}]