You can't imagine _____when they received these nice Christmas presents.[ ]

A. how they were excited

B. how excited they were

C. how excited were they

D. they were how excite

下列有关物质检验的结论中正确的是[ ]

A．某物质进行焰色反应实验时，焰色为紫色,表明该物质中含KCl

B．某无色气体与空气混合后，有红棕色气体生成，说明该气体是NO

C．某溶液中滴入BaCl₂溶液，生成不溶于稀硝酸的沉淀，表明该溶液含SO₄^2-

D．某气体通入品红溶液，溶液褪色，说明该气体是SO₂