+CO →△AlCl3,HCl →OH−,△CH3CHO B →②H+①C →浓硫酸,△CH3OH E
已知:HCHO+CH3CHO →OH−,△ CH2═CHCHO+H2O
设a>1,则log0.2a、0.2a、a0.2的大小关系是( )