Question: when can the sun's corona best be seen
[{'answer': 'during a total solar eclipse', 'provenance': [{'wikipedia_id': '7839', 'title': 'Corona', 'start_paragraph_id': 1, 'start_character': 250, 'end_paragraph_id': 1, 'end_character': 278, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '7839', 'title': 'Corona', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 324, 'bleu_score': 0.7015620074548411, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18028545568140897194}, 'section': 'Section::::Abstract.'}]}]