鉴别下列各组物质,选用的试剂(在括号内)不合理的是
A:CO2和N2(澄清石灰水)
B:Ca(OH)2溶液和NaOH溶液(稀盐酸)
C:NaOH溶液和稀H2SO4(pH试纸)
D:固体CaCO3和固体Na2CO3(水)
第一节在全诗中的作用是什么?
Feeling lonely may have some effects on a child's characters, however, it is not always permanent.