Question: when does lexie grey join grey's anatomy
[{'answer': 'season three', 'provenance': [{'wikipedia_id': '11340577', 'title': 'Lexie Grey', 'start_paragraph_id': 1, 'start_character': 232, 'end_paragraph_id': 1, 'end_character': 244, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '11340577', 'title': 'Lexie Grey', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 676, 'bleu_score': 0.7956454949850731, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14883627694801449138}, 'section': 'Section::::Abstract.'}]}]