怎样修改word文档的背景？

[[{"txt": "\u6709\u65f6\u5019\u7528word\u60f3\u8981\u6709\u4e00\u4e2a\u597d\u770b\u7684\u80cc\u666f\uff0c\u8fd9\u6837\u770b\u7740\u5fc3\u60c5\u4e5f\uff0c\u90a3\u4e48\u5982\u4f55\u66f4\u6539\u6587\u6863\u80cc\u666f\uff1f"}], [{"txt": ["\u5de5\u5177/\u539f\u6599"]}, {"txt": "word"}, {"txt": "\u7535\u8111"}], [{"txt": ["\u65b9\u6cd5/\u6b65\u9aa4"]}, {"txt": "1.\u66f4\u6539\u80cc\u666f\u53ef\u4ee5\u66f4\u6539\u989c\u8272\u6216\u8005\u63d2\u5165\u56fe\u7247\u51e0\u79cd\u90fd\u662f\u53ef\u4ee5\u7684\uff0c\u4e0b\u9762\u8bb2\u989c\u8272\uff0c\u6211\u4eec\u9996\u5148\u6253\u5f00\u4e00\u4e2a\u6587\u6863"}, {"img": ["https://exp-picture.cdn.bcebos.com/125ed0ecd3d96975eef79d2cd243040149fe0988.m2m?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_500%2Climit_1"]}, {"txt": "2.\u9009\u62e9\u9875\u9762\u5e03\u5c40\uff0c\u7136\u540e\u9009\u62e9\u80cc\u666f"}, {"img": ["https://exp-picture.cdn.bcebos.com/054056fe1e425d6b27e2389c11883913e9e50088.m2m?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_500%2Climit_1"]}, {"txt": "3.\u9009\u62e9\u989c\u8272\u5c31\u53ef\u4ee5\u9009\u62e9\u6709\u7684\u989c\u8272\u6216\u8005\u76f4\u63a5\u81ea\u5b9a\u4e49\u989c\u8272\u90fd\u662f\u53ef\u4ee5\u7684\uff0c\u9009\u597d\u786e\u5b9a\u5c31\u53ef\u4ee5\u4e86\uff0c\u89c1\u4e0b\u56fe"}, {"img": ["https://exp-picture.cdn.bcebos.com/9bc92713e8e5ecee848fcf9acc704618deda7a88.m2m?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_500%2Climit_1", "https://exp-picture.cdn.bcebos.com/de9bfa3b3b8602217e64e2e3d8bbf82065fb7288.m2m?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_500%2Climit_1"]}, {"txt": "4.\u4e5f\u53ef\u4ee5\u63d2\u5165\u56fe\u7247\u5f53\u80cc\u666f\u8272\uff0c\u9009\u62e9\u80cc\u666f\u91cc\u9762\u7684\u56fe\u7247\u7136\u540e\u9009\u62e9\u56fe\u7247"}, {"img": ["https://exp-picture.cdn.bcebos.com/65ba880b312105613d90245c08aee8d7582a6a88.m2m?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_500%2Climit_1"]}, {"txt": "5.\u9009\u62e9\u597d\u9700\u8981\u7684\u56fe\u7247\u7136\u540e\u63d2\u5165\uff0c\u5b8c\u6210\u540e\u80cc\u666f\u5c31\u53d8\u6210\u63d2\u5165\u7684\u56fe\u7247\u4e86"}, {"img": ["https://exp-picture.cdn.bcebos.com/586bfdefe07814319e8543d9dc6699cf03536288.m2m?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_500%2Climit_1", "https://exp-picture.cdn.bcebos.com/031231632385e036aba2365db8e039723c035a88.m2m?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_500%2Climit_1", "https://exp-picture.cdn.bcebos.com/38332303bbea3e86607b10f65cd4483105eb5588.m2m?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_500%2Climit_1"]}], [{"txt": ["\u6ce8\u610f\u4e8b\u9879"]}, {"txt": "\u672c\u7ecf\u9a8c\u5982\u679c\u5bf9\u4f60\u6709\u5e2e\u52a9\uff0c\u6b22\u8fce\u6295\u7968\uff01\u70b9\u8d5e\uff01\u5173\u6ce8\uff01\u6709\u7591\u95ee\u53ef\u7559\u8a00"}]]