A:R
B:2R
C:4R
D:8R
下列物质中所含的氮元素的化合价共有几种( )N2 NO2 NO N2O N2O3 NH3 N2O5 NH4NO3
恒温动物比变温动物更有生存优势的原因在于( )
54的 23 相当于90的多少?
You had better _________ wine because you have to drive back home.