tarnishes
n.
污点，瑕疵，无光泽( tarnish的名词复数 );
v.
（通常指金属）（使）失去光泽，（使）变灰暗( tarnish的第三人称单数 );
玷污，败坏;
例句:
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It never rusts or tarnishes.
它从不生锈，也不会失去光泽。
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Brass tarnishes quickly in wet weather.
天气潮湿时黄铜很快会失去光泽.
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This metal tarnishes easily.
这种金属易变色.
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It tarnishes Chinese image real badly in the eyes of the world.
来自SA
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Inevitably, because half of the album stinks it completely tarnishes the good songs.
来自BBC
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Only cigarettes, which he has failed to quit, tarnishes his healthy regime.
来自THETIMES