A:加热NaHCO3制CO2
B:用Cu与稀HNO3反应制NO
C:用NH4Cl与浓NaOH溶液反应制NH3
D:用NaCl与浓H2SO4反应制HCl
This is Mr White's ________ trip to Beijing. He has been there twice before.
下图表示“制作洋葱鳞片叶表皮细胞临时装片”实验的部分操作步骤,步骤②和④滴加的液体分别是( )