太阳是太阳系的中心天体,地球是太阳系的八颗行星之一. 太阳活动会引起地球大气电离层扰动而导致( )
A:“磁暴”现象
B:极光现象
C:无线电短波通信衰减或中断现象
D:耀斑现象
Present at the historic meeting ________ many an official on Nov 7, of course President Xi Jinping and Ma Ying-jeou ________.
2NH3(g)+CO2(g)═CO(NH2)2(s)+H2O(g)
下列递变规律正确的是( )