A:Fe+CuSO4=FeSO4+Cu
B:Fe2O3+3CO2Fe+3CO2
C:AgNO3+NaCl=AgCl↓+NaNO3
D:2KMnO4K2MnO4 +MnO2 +O2↑
读我国西北、青藏地区图,回答下列问题
Most of the time, he has no trouble ______________ the people from different countries.