如果有个更安全的方法会怎样？
如果用盖子或者大桶，学生不是拧不开，就是容易发生意外。[{'character': '如', 'pinyin': 'ru2', 'highest pitch': 9.4, 'lowest pitch': 8.37, 'duration': 0.18, 'prosody hierarchy': 'null'}, {'character': '果', 'pinyin': 'guo3', 'highest pitch': 8.86, 'lowest pitch': 6.15, 'duration': 0.28, 'prosody hierarchy': '#2'}, {'character': '用', 'pinyin': 'iong4', 'highest pitch': 9.43, 'lowest pitch': 6.85, 'duration': 0.21, 'prosody hierarchy': '#1'}, {'character': '盖', 'pinyin': 'gai4', 'highest pitch': 10.97, 'lowest pitch': 7.8, 'duration': 0.28, 'prosody hierarchy': 'null'}, {'character': '子', 'pinyin': 'zii5', 'highest pitch': 7.8, 'lowest pitch': 6.23, 'duration': 0.21, 'prosody hierarchy': '#1'}, {'character': '或', 'pinyin': 'huo4', 'highest pitch': 13.4, 'lowest pitch': 7.14, 'duration': 0.19, 'prosody hierarchy': 'null'}, {'character': '者', 'pinyin': 'zhe3', 'highest pitch': 7.66, 'lowest pitch': 6.2, 'duration': 0.11, 'prosody hierarchy': '#1'}, {'character': '大', 'pinyin': 'da4', 'highest pitch': 9.98, 'lowest pitch': 6.26, 'duration': 0.21, 'prosody hierarchy': 'null'}, {'character': '桶', 'pinyin': 'tong3', 'highest pitch': 7.15, 'lowest pitch': 3.23, 'duration': 0.33, 'prosody hierarchy': '#3'}, {'pinyin': 'sp1', 'highest pitch': 0.0, 'lowest pitch': 0.0, 'duration': 0.18}, {'character': '学', 'pinyin': 'xve2', 'highest pitch': 6.95, 'lowest pitch': 6.11, 'duration': 0.23, 'prosody hierarchy': 'null'}, {'character': '生', 'pinyin': 'sheng1', 'highest pitch': 9.62, 'lowest pitch': 6.95, 'duration': 0.25, 'prosody hierarchy': '#2'}, {'pinyin': 'sp1', 'highest pitch': 0.0, 'lowest pitch': 0.0, 'duration': 0.06}, {'character': '不', 'pinyin': 'bu2', 'highest pitch': 9.71, 'lowest pitch': 7.24, 'duration': 0.16, 'prosody hierarchy': 'null'}, {'character': '是', 'pinyin': 'shiii4', 'highest pitch': 11.53, 'lowest pitch': 9.71, 'duration': 0.14, 'prosody hierarchy': '#1'}, {'character': '拧', 'pinyin': 'ning3', 'highest pitch': 10.72, 'lowest pitch': 5.09, 'duration': 0.21, 'prosody hierarchy': 'null'}, {'character': '不', 'pinyin': 'bu4', 'highest pitch': 6.35, 'lowest pitch': 5.53, 'duration': 0.13, 'prosody hierarchy': 'null'}, {'character': '开', 'pinyin': 'kai1', 'highest pitch': 8.43, 'lowest pitch': 7.85, 'duration': 0.32, 'prosody hierarchy': '#3'}, {'pinyin': 'sp1', 'highest pitch': 0.0, 'lowest pitch': 0.0, 'duration': 0.13}, {'character': '就', 'pinyin': 'jiou4', 'highest pitch': 7.59, 'lowest pitch': 6.57, 'duration': 0.16, 'prosody hierarchy': 'null'}, {'character': '是', 'pinyin': 'shiii4', 'highest pitch': 11.53, 'lowest pitch': 5.63, 'duration': 0.13, 'prosody hierarchy': '#1'}, {'character': '容', 'pinyin': 'rong2', 'highest pitch': 6.39, 'lowest pitch': 5.19, 'duration': 0.15, 'prosody hierarchy': 'null'}, {'character': '易', 'pinyin': 'i4', 'highest pitch': 9.94, 'lowest pitch': 6.39, 'duration': 0.14, 'prosody hierarchy': '#1'}, {'character': '发', 'pinyin': 'fa1', 'highest pitch': 8.69, 'lowest pitch': 7.33, 'duration': 0.2, 'prosody hierarchy': 'null'}, {'character': '生', 'pinyin': 'sheng1', 'highest pitch': 9.62, 'lowest pitch': 8.62, 'duration': 0.19, 'prosody hierarchy': '#1'}, {'character': '意', 'pinyin': 'i4', 'highest pitch': 9.94, 'lowest pitch': 9.16, 'duration': 0.14, 'prosody hierarchy': 'null'}, {'character': '外', 'pinyin': 'uai4', 'highest pitch': 10.6, 'lowest pitch': 6.8, 'duration': 0.27, 'prosody hierarchy': '#4'}]