选项
物质
杂质
除杂方法
A
H2
HCl
通过饱和的Na2CO3溶液
B
KNO3晶体
NaCl
高温下制成饱和溶液,降温结晶,过滤,洗涤烘干
C
NaCl晶体
Na2CO3
加稍过量稀盐酸,蒸发结晶
D
KCl溶液
K2SO4
加稍过量Ba(NO3)2溶液,过滤
A:What do you want to do in the future, Allen? B:I want to _ a Hope School to help students who are unable to go to school.
根据题意,补全对话。
—How many pandas were there?
—____ .(一千六百只)
小明在用双氧水制氧气的实验中,忘记放入二氧化锰,其结果是( )