R-12 is generally considered to be a safe, nontoxic, nonflammable, and non-explosive refrigerantIt can, however, become highly toxic when ().

A . superheated outside the system B . in contact with an open flame C . heated to the boiling point D . All of the above

时间:2022-10-20 15:22:16 所属题库:船舶辅助机械题库

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