A:∅
B:{3,4}
C:{1,2}
D:{0,4}
下列符合题意的化学方程式书写及其所属反应类型均正确的是( )
My Tuesday Morning
Chinese class
8: 20 a.m. (上午)
English class
9:10 a.m.
Music class
10:20 a.m.
P. E.
11:10 a.m.
例:After Chinese class, I have English class.
Before English class, I have Chinese class.
怎样用最简单的化学方法区别铁、生铁(或钢)?