Gas masks ___________.(1.0)
A.should be worn while fighting a fire B.can be used in atmospheres deficient in oxygen C.filter contaminants from air that is to be breathed D.may be substituted for a self-contained breathing apparatus正确答案C
Gas masks ___________.(1.0)
A.should be worn while fighting a fire B.can be used in atmospheres deficient in oxygen C.filter contaminants from air that is to be breathed D.may be substituted for a self-contained breathing apparatus正确答案C
