研究人员发现，只有有限的证据表明，舒适性较差而且昂贵的N95口罩效果优于手术用口罩。
The researchers found only limited evidence that so-called N95 facial masks, which are uncomfortable and expensive, are better than simple surgical masks.
一位穿着实验室白大褂、戴着手术口罩的中年妇女从中拿出几个试管，离我脸一英尺远挥舞着，用乌克兰语说着什么。
A middle-aged woman in a lab coat and surgical mask pulled a few test tubes from the freezer, waving them around a foot from my face and saying something in Ukrainian.
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