《报检员证》的有效期为2年，期满之日前（）天，报检员应向发证检验检疫机构提出审核申请，同时提交审核申请书。

A．15

B．20

C．30

D．60

Halon fire extinguishers are NOT effective when used on which types of fires?（）

A.Fires in electrical equipment

B.Flammable oils and greases

C.Class "A" fires in ordinary combustibles

D.Materials containing their own oxygen