碳酸钠从溶液里结晶析出时，晶体里总是结合着一定数目的水分子（结晶水），随温度变化可分别得到Na₂CO₃•10H₂O、Na₂CO₃•7H₂O和Na₂CO₃•H₂O三种晶体．分析碳酸钠溶解度随温度变化曲线（见图）得到的下列说法，正确的是（　　）

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化学是一门以实验为基础的学科，化学所取得的丰硕成果，是与实验的重要作用分不开的．结合下列实验装置图，回答问题：

B

Dear Tom,

    Thanks for your letter. Do you want to know about my evening? Well, I usually get home from work at 6:00 p.m. I cook dinner for my family—my parents, my sister, and my brother. After dinner I usually watch TV, play computer games or play chess. I like playing chess because my father works in a chess club. I take a shower at around nine o'clock and then go to bed at around nine thirty. Sometimes I read some books because I can learn something about my work. How about your evening? Write to me soon, please.

Best wishes,

Victor