A:S+O2↑ →点燃 SO2
B:2H2+O2 →点燃 2H2O
C:6Fe+4O2 →点燃 2Fe3O4
D:Mg+O2 →点燃 MgO2
如图为人体血液循环示意图,据图回答有关问题:
— Mum, I've got a chance to be an exchange student to the UK next year!
— Really? That's just ________ to be true. Anyway, congratulations, baby!