A:NH4Cl与Ba(OH)2•8H2O研磨
B:生石灰溶于水
C:镁与稀盐酸反应
D:甲烷燃烧
造纸厂去年计划造纸1600吨,实际造纸1800吨,实际超产百分之几?
He thinks art lesson is ____ (important), so he usually sleeps in it.