A:C103p3(1-p)7
B:C103p7(1-p)3
C:p3(1-p)7
D:p7(1-p)3
通过一步反应不能直接完成的是( )
①N2→NO2②S→SO2 ③NH3→NO④NO→HNO3⑤CuSO4→Cu(NO3)2⑥SiO2→H2SiO3.
I asked Tim _____ he would go back to England for Christmas this year.
若X为铜,为减缓铁的腐蚀,开关K应置于____ 处;若X为锌棒,开关K置于M处,该电化学防护法称为____