A.甲烷燃烧生成二氧化碳和水
B.铁能在氧气中燃烧
C.白磷的着火点比红磷的低
D.氧气约占空气质量的15
A:A
B:B
C:C
D:D
语文实践活动
— What are you doing Daming?
— I'm _________ an email to my friend. ( )