The use of bitmask atomic operations is slightly different than arithmetic because only two operations are available (set mask and clear mask).

位掩码原子操作的使用跟算术操作存在细微的差别，因为其中只有两个可用的操作(设置掩码和清除掩码)。

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In this case, a full-face respirator is called for. It provides a clear face mask or clear eye pieces that protect the eyes as well.

这种情况下需要用到全面罩呼吸器，可以提供透明面罩或者只是眼部透明，就同时保护了眼睛。

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Prevent pale, dull and lifeless "mask makeup", and make skin clear and lustrous for a whole day.

告别苍白、灰暗和令人生畏的“面具妆容”，肌肤全天候焕发浑然天成的清透光彩。

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"He was very distressed and totally aware of his situation and, although unable to speak because of the oxygen mask, he made it clear he was cold and wanted to come home, " she added.

BBC: Age Cymru's NHS patient dignity training call

However, he warned that if there were further, larger eruptions of ash, people with lung problems such as asthma should "stay clear of the ash" by staying indoors and wearing a mask.

BBC: Mount St Helens spews out steam and ash on 5 October 2004