No one taught French. He learned it all by .
A:himself; him
B:he; himself
C:him; himself
已知:3CH4(g)+2N2(g)⇌3C(s)+4NH3(g)△H>0,700℃时,CH4与N2在不同物质的量之比 nCH4nN2时CH4的平衡转化率如图所示.下列说法正确的是( )