题干

过滤操作的下列步骤中错误的是(   )

A:取一张圆形滤纸,对折两次,打开成圆锥形,放入漏斗

B:如果滤纸高于漏斗边缘,用剪刀剪去多余部分,使滤纸的边缘比漏斗口稍低

C:用少量水润湿滤纸,使滤纸紧贴漏斗,滤纸层与漏斗壁间不留气泡

D:用玻璃棒轻轻搅动漏斗中的液体,以加快过滤

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答案(点此获取答案解析)

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.