Question: when will the metro line to dulles be finished
[{'answer': 'sometime in 2020', 'provenance': [{'wikipedia_id': '4002166', 'title': 'Silver Line (Washington Metro)', 'start_paragraph_id': 2, 'start_character': 420, 'end_paragraph_id': 2, 'end_character': 436, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '4002166', 'title': 'Silver Line (Washington Metro)', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 536, 'bleu_score': 0.721288334693572, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13357509017222807700}, 'section': 'Section::::Abstract.'}]}]