题目

7．Are your children liked by their teachers？All parents want their children to impress their teachers and succeed in sch001．You can get your children to impress their teachers by following these easy steps．Make sure they're prepared．Teachers are impressed by children coming to schoolprepared to learn．Make sure they have everything they need：pencils，textbooks，erasers，and so on．Require them to be active in class．Teach them to ask teachers questions when they don't understand something．Some children think teachers are bothered by questions，but most teachers are impress下列分别盛有不同物质的容器中，所盛物质属于单质的是_____，属于混合物的是_____，属于氧化物的是_____．(填字母)