Question: when does addison come back to grey's anatomy season 4
[{'answer': 'May 1 , 2008', 'provenance': [{'wikipedia_id': '11058032', 'title': "Grey's Anatomy (season 4)", 'start_paragraph_id': 61, 'start_character': 407, 'end_paragraph_id': 61, 'end_character': 428, 'bleu_score': 1.0, 'section': 'Section::::Cast.:Guest cast.\n'}]}, {'provenance': [{'wikipedia_id': '11058032', 'title': "Grey's Anatomy (season 4)", 'start_paragraph_id': 61, 'start_character': 0, 'end_paragraph_id': 61, 'end_character': 808, 'bleu_score': 0.983672097934538, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8954022168783052114}, 'section': 'Section::::Cast.:Guest cast.\n'}]}]