读图，回答问题．
根据文章意思，正确排序。
①Yes, we have a new music teacher.
②Do you like her?
③Is she old?
④Do you have new teachers?
⑤ No, she isn’t. She is funny.
⑥Yes, we all like her.
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，每个编号代表下列物质中的一种物质，凡是用直线相连的两种物质均能发生化学反应。供选择的物质有：a．铁；b．稀H2SO4；c．Na2CO3溶液；d．BaCl2溶液；e．Cu(NO3)2溶液；f．MgSO4溶液。图中编号④代表的物质是
