A:Ba(NO3)2+H2SO4═BaSO4↓+2HNO3
B:BaCl2+Na2SO4═BaSO4↓+2NaCl
C:BaCO3+H2SO4═BaSO4↓+H2O+CO2↑
D:BaCl2+H2SO4═BaSO4↓+2HCl
小莉的妈妈一直注意给她加喂钙粉,可医生还是诊断小莉缺钙,原因是在服用钙粉时没有补充( )
Please post this letter in the post office nearby, and __________, I will get two tickets in the train station. ( )
关于黄土高原地面景观的叙述,正确的是