只用一种试剂就可鉴别NaCl、NH4Cl、Na2CO3三种溶液，该试剂是（ ）
A．KCl溶液
B．Ba（OH）2 溶液
C．NaOH溶液
D．NaNO3溶液
答案：B
题目分析：A．KCl溶液与三种物质均不反应，无明显变化。无法区别三种特。此项不正确。B．Ba(OH)2 溶液不与氯化钠氯化钠溶液反应；可与氯化铵溶液生成有刺激性气味的气体；与碳酸钠溶液可生成沉淀。现象明显不同，可进行鉴别。此项正确。C．NaOH溶液不与氯化钠氯化钠溶液反应；可与氯化铵溶液生成有刺激性气味的气体；与碳酸钠溶液不反应。只有与氯化铵现象明显不同，无法鉴别另外两种物质。此项不正确。D．NaNO3溶液与三种物质均不反应，无明显变化。无法区别三种特。此项不正确。所以应选B项。
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| A businesswoman got into a taxi in midtown. As it was the rush hour and she was in a 1 to catch a train, she 2 a quick way to reach it. "I have been a taxi driver for 15 years!" the driver said 3 . "You don't think I know the best way to go?" The woman tried to explain that she hadn't 4 to annoy him, but the driver kept 5 . She finally realized that he was too annoyed to be 6 , so she changed her 7 . "You know, you are right," she told him. "It must seem 8 for me not to think you know the best way 9 the city." 10 , the driver glanced at his 11 in the rearview mirror (后视镜), turned down the street she wanted and got her to the train on time. "He didn't say another word the rest of the ride," she said, " 12 I got out and paid him. Then he thanked me." When you find yourself 13 with people like the taxi driver, you will always try to 14 your idea. It can lead to longer arguments, lose job chances or even 15 marriages. I have discovered one simple 16 extremely effective method that can prevent the disagreement or other difficult situations from 17 in a disaster. The 18 is to put yourself in the other person's shoes and look for the 19 in what that person is saying. Find a way to 20 , and the result may surprise you. | ||||
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