Question: when will silver line to dulles be finished
[{'answer': '2018', 'provenance': [{'wikipedia_id': '4002166', 'title': 'Silver Line (Washington Metro)', 'start_paragraph_id': 23, 'start_character': 162, 'end_paragraph_id': 23, 'end_character': 166, 'bleu_score': 1.0, 'section': 'Section::::History.:Construction.\n'}]}, {'provenance': [{'wikipedia_id': '4002166', 'title': 'Silver Line (Washington Metro)', 'start_paragraph_id': 26, 'start_character': 0, 'end_paragraph_id': 26, 'end_character': 306, 'bleu_score': 0.8358213710926451, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11970314133298048602}, 'section': 'Section::::History.:Construction.\n'}]}]