单项选择题
A.3g,2hB.6g,2hC.6g,10hD.6g,20h
A.25℃,21天B.25℃,49天C.40℃,21天D.40℃,49天
A.-18℃,U10s≥7.2VB.-18℃,U30s≥7.2VC.-29℃,U10s≥7.2VD.-29℃,U30s≥7.2V