题目

My mother is a diligent and kind woman. She is very busy from morning till night. As a teacher, she works hard. ___29___ Both my brother and I love her dearly as she loves us. My mother has been teaching math at a middle school in my hometown. She goes to work early in the morning and does not return home until late in the afternoon. ___30___ She treats them with patience and teaches them well. For her excellent quality and very good teaching results, she has been elected as a model teacher several times. ___31___ Every day, when she comes back home from work, she sets about doing house有三瓶失去标签的无色溶液，只知道它们分别是KCl溶液、Na2CO3溶液和Ba(NO3)2溶液中的各一种。下列四种试剂中，能将上述三种无色溶液一次鉴别出来的是A．澄清石灰水 B．稀盐酸 C．稀硫酸 D．酚酞试液