Dolly is a middle school girl. Her parents want to take her to Ice and Snow Festival. How much will they pay for the tickets?
A:¥20.
B:¥30.
C:¥50
D:¥60
CoCl2+H2O⇌CoCl2•xH2O深蓝色现有65g无水CoCl2,吸水后变成CoCl2•xH2O 119g.
8n是整数,正整数n的最小值是( )
在一定区域范围内,城市的等级越高,城市( )