Question: when did the us start trading with china
[{'answer': '1979', 'provenance': [{'wikipedia_id': '277880', 'title': 'China–United States relations', 'start_paragraph_id': 48, 'start_character': 247, 'end_paragraph_id': 48, 'end_character': 251, 'bleu_score': 1.0, 'section': 'Section::::History.:The Republic of China and the United States.:Cold War relations.\n'}]}, {'provenance': [{'wikipedia_id': '277880', 'title': 'China–United States relations', 'start_paragraph_id': 92, 'start_character': 0, 'end_paragraph_id': 92, 'end_character': 447, 'bleu_score': 0.9716239638199891, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8153096108072049248}, 'section': "Section::::History.:The People's Republic of China and the United States.:Normalization.\n"}]}]