Sir, you ______be sitting in this waiting-room. It is for women and children only. A. oughtn’t to B. can’t C. won’t D. needn’t 答案:A(2011年湖北黄冈,12题,2分)下列各级物质的溶液不用其它试剂就可鉴别的是:A.HClCuCl2NaNO3 Na2SO4B.BaCl2 Na2CO3 HCl (NH4)2CO3C.FeCl3 HClNaClNaOHD.Na2CO3Na2SO4HClH2SO4