Question: who plays leonard on the big bang theory
[{'answer': 'John Mark Galecki', 'provenance': [{'wikipedia_id': '2318278', 'title': 'Johnny Galecki', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 17, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '2318278', 'title': 'Johnny Galecki', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 427, 'bleu_score': 0.7628233842026381, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12813001747870909648}, 'section': 'Section::::Abstract.'}]}]