Question: where did the german luftwaffe focus their bombing in great britain
[{'answer': 'London', 'provenance': [{'wikipedia_id': '57974', 'title': 'Battle of Britain', 'start_paragraph_id': 18, 'start_character': 664, 'end_paragraph_id': 18, 'end_character': 670, 'bleu_score': 1.0, 'section': 'Section::::Background.:German aims and directives.\n'}]}, {'provenance': [{'wikipedia_id': '57974', 'title': 'Battle of Britain', 'start_paragraph_id': 69, 'start_character': 0, 'end_paragraph_id': 69, 'end_character': 782, 'bleu_score': 0.9844346099707091, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2274394814854206911}, 'section': 'Section::::Luftwaffe strategy.\n'}]}]