A:Knowing
B:Know
C:To know
D:Knew
生命在生物圈中的延续和发展,最基本的环节是生物通过____和____世代相续,生生不息.
物质
选项
甲
乙
丙
丁
A
CO2
CaCO3
H2O
O2
B
NaOH
NaCl
Na2CO3
C
H2O2
MgO
D
CaO
Ca(OH)2
CaCl2
The party is a great _________. We've had a good time.
16的算术平方根和25的平方根的和是( )