题目

 下列各组离子在溶液中能大量共存的是 A. H+、Fe2+、Cl-、NO3-    B. Mg2+、K+、OH-、Cl- C. NH4+、Ca2+、NO3-、CO32-    D. K+、H+、Cl-、SO42- 答案：【答案】D 【解析】A、 H+、NO3-  组成HNO3将Fe2+氧化，故A错误；  B. Mg2+与OH-生成Mg(OH)2 沉淀，故B错误；C. Ca2+、CO32-  生成CaCO3沉淀，故C错误；  D. K+、H+、Cl-、SO42-不能生成沉淀、气体和水，故D正确；故选D。根据短文内容选择方框内的单词,并用其正确的形式填入空白处(每空填一词)，使补全后的短文意思通顺，语法正确，结构完整。work   cup   famous     improve    himselfLiu Qian is a magician from Taiwan. He is  小题1:  for his magic shows. Now everyone is interested in magic. We all want to know how to do a trick! From     小题2: to coins and to rubber bands (皮筋), it seems that anything can be used in a trick. Liu didn't go to any magic schools. He learned by  小题3:. He practices hard. Now he is a great magician. When Liu was seven, he saw a coin trick in a big store. At that moment Liu decided to learn magic. Liu practiced hard to  小题4:  his skills. Then one day he put on a show for his class. "There was the surprise on everyone's face. It was cool." Liu still   小题5:  hard at magic today. He may spend three years working on a new show.