Question: what did germany do to try to prevent goods from reaching great britain
[{'answer': 'commerce raiders', 'provenance': [{'wikipedia_id': '17310823', 'title': 'Blockade of Germany', 'start_paragraph_id': 2, 'start_character': 548, 'end_paragraph_id': 2, 'end_character': 564, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'unrestricted submarine warfare', 'provenance': [{'wikipedia_id': '17310823', 'title': 'Blockade of Germany', 'start_paragraph_id': 2, 'start_character': 569, 'end_paragraph_id': 2, 'end_character': 599, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '17310823', 'title': 'Blockade of Germany', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 609, 'bleu_score': 0.9081960746110761, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13745237718132152212}, 'section': 'Section::::Abstract.'}]}]