35 当压力较低,介质无毒、非易燃易爆时,采用石墨石棉或 橡胶石棉为垫料;当压力较高,介质有毒、易燃易爆时,采用石棉和 油浸石棉。
A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
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