Question: who did guam belong to before the us
[{'answer': 'Spain', 'provenance': [{'wikipedia_id': '11974', 'title': 'Guam', 'start_paragraph_id': 3, 'start_character': 139, 'end_paragraph_id': 3, 'end_character': 144, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '11974', 'title': 'Guam', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 687, 'bleu_score': 0.9509503382229441, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1639124391721901861}, 'section': 'Section::::Abstract.'}]}]