最近，人民币对美元的汇率是怎样的？
一直以来，人民币对美元升多贬少。[{'character': '一', 'pinyin': 'i4', 'highest pitch': 10.63, 'lowest pitch': 8.5, 'duration': 0.14, 'prosody hierarchy': 'null'}, {'character': '直', 'pinyin': 'zhiii2', 'highest pitch': 10.09, 'lowest pitch': 8.5, 'duration': 0.16, 'prosody hierarchy': '#1'}, {'character': '以', 'pinyin': 'i3', 'highest pitch': 9.84, 'lowest pitch': 7.09, 'duration': 0.1, 'prosody hierarchy': 'null'}, {'character': '来', 'pinyin': 'lai2', 'highest pitch': 7.89, 'lowest pitch': 5.95, 'duration': 0.32, 'prosody hierarchy': '#3'}, {'pinyin': 'sp1', 'highest pitch': 0.0, 'lowest pitch': 0.0, 'duration': 0.1}, {'character': '人', 'pinyin': 'ren2', 'highest pitch': 10.29, 'lowest pitch': 8.46, 'duration': 0.19, 'prosody hierarchy': 'null'}, {'character': '民', 'pinyin': 'min2', 'highest pitch': 10.29, 'lowest pitch': 9.46, 'duration': 0.19, 'prosody hierarchy': 'null'}, {'character': '币', 'pinyin': 'bi4', 'highest pitch': 9.84, 'lowest pitch': 8.09, 'duration': 0.18, 'prosody hierarchy': '#1'}, {'character': '对', 'pinyin': 'duei4', 'highest pitch': 9.38, 'lowest pitch': 8.09, 'duration': 0.13, 'prosody hierarchy': '#1'}, {'character': '美', 'pinyin': 'mei3', 'highest pitch': 8.12, 'lowest pitch': 4.25, 'duration': 0.21, 'prosody hierarchy': 'null'}, {'character': '元', 'pinyin': 'van2', 'highest pitch': 7.98, 'lowest pitch': 4.36, 'duration': 0.28, 'prosody hierarchy': '#2'}, {'character': '升', 'pinyin': 'sheng1', 'highest pitch': 10.22, 'lowest pitch': 9.96, 'duration': 0.26, 'prosody hierarchy': 'null'}, {'character': '多', 'pinyin': 'duo1', 'highest pitch': 10.53, 'lowest pitch': 10.17, 'duration': 0.15, 'prosody hierarchy': '#1'}, {'character': '贬', 'pinyin': 'bian2', 'highest pitch': 9.04, 'lowest pitch': 6.48, 'duration': 0.22, 'prosody hierarchy': 'null'}, {'character': '少', 'pinyin': 'shao3', 'highest pitch': 9.04, 'lowest pitch': 2.79, 'duration': 0.35, 'prosody hierarchy': '#4'}]