reddens
v.
（使）变红( redden的第三人称单数 );
（由于羞愧、愤怒、天气热等）脸变红;
例句:
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If you mention any possible lacuna or shortcoming, his face reddens and he offers a well-thought-through rebuttal.
来自NEWYORKER
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I asked if her face reddens when she runs, and she said no, although it will if she stands on her head.
来自NEWYORKER