题干

下列物质的鉴别方法正确的是                                          

A:用澄清石灰水鉴别氢气和一氧化碳

B:用无色酚酞鉴别碳酸钠溶液和氢氧化钠溶液

C:用食盐水鉴别硬水和软水

D:用水鉴别硝酸铵固体和氢氧化钠固体

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D

同类题1

阅读下面材料,在空白处填入适当的内容(1个单词)或括号内单词的正确形式。

           We're human, and it's not always easy to get along with everyone all the time.Sometimes we hurt other people's feelings without intending to. Sometimes,we're ____(deliberate) mean and we feel bad afterward. So we apologize. Apologies are one of the tools we use to build good friendships andrelationships. ____ you say“I'm sorry” (and really mean it), it's because youprobably feel bad that something you did or said hurt the other person. Sayingyou're sorry is more than just words. You're also saying that you respect theother person  ____  you care about his or her feelings.Apologizing shows you have empathy.

     After  apologizing,you might feel alittle ____(good).The other personprobably will, too. When you apologize in a caring way, you can feel goodbecause you are trying to make things right again.

     Some times a heartfelt“I'm sorry” ____(fix) everything right away. Other times,it might take  ____while for someone to get past feeling upset. You may need to give the otherperson some time. Even after you say you're sorry, you might still feel bad aboutwhat you said or did—but you can feel good about apologizing, fixing themistake, or making up your ____ to do better. When someone apologizes to you,you may welcome it and be ready to forgive  ____ happened and move on. Or you might not feel like being friendly againright away. If a person keeps hurting you and ____ (apologize)without making aneffort to change,you might not want tohang about ____  that person any more.