题目

下列属于氧化还原反应的是 A.CaCO3CaO+CO2↑       B.Na2O+H2O＝2NaOH C.Na2CO3+H2SO4＝.Na2SO4+CO2↑+H2O      D.MnO2+4HCl MnCl2+Cl2↑+2H2O 答案：DEnglish will help us ______ in our work and study.A. lot B. a lot C. a lot of D. lots of