A：Ba(OH)2+CO2=BaCO3↓+H2O
B：Ba(HCO3)+Ba(OH)2 = 2BaCO3↓+2H2O
C：Ba(NO3)2+ Na2CO3= BaCO3↓+2NaNO3
D：Ba(OH)2+ 2KHCO3 = BaCO3↓+KOH+H2O
The Red Army soldiers had to fight ________ all kinds of difficulties in their fight ________ the people's freedom.
填上合适的介词。
M ____ mouth.
外加生长素（mg/L）
0
1
2
3
4
5
6
7
花粉管平均长度（mm）
0.2
3.6
5.5
6.4
5.2
3.1
0.4
由表中数据得到的结论中正确的是（ ）
