We _ for dinner yesterday. [ ]
A. have a
B. had fishes
C. had fish
D. have fish
答案:C
对于X+Y(g)⇌Z的平衡,若增大压强,Y的转化率不变,则X和Z可能的状态是( )
A.X为固态,Z为固态
B.X为固态,Z为气态
C.X为气态,Z为气态
D.无法确定
安全阀铭牌的主要内容有哪些?