A:2NaCl(熔融)2Na + Cl2↑
B:Al2O3 + 3H22Al + 3H2O
C:Fe3O4 + 4CO3Fe + 4CO2
D:2HgO2Hg + O2↑
10个一万是____ 10个一千万是____
一百万是10个____ 十亿是10个____
—I haven't worked the problem out yet. What am I supposed to do?
—Try again! It’s only difficult.