设计实验方案是科学探究的重要环节，以下设计中不能达到实验目的_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题选择题

设计实验方案是科学探究的重要环节，以下设计中不能达到实验目的是

A．可以用适量石灰水检验并除去氢氧化钠中混有的少量碳酸钠

B．用燃烧的方法除去二氧化碳中混有的少量一氧化碳

C．用水鉴别硝酸铵固体和氢氧化钠固体

D．加过量的稀盐酸除去铜粉中混有的少量铁粉

答案

答案：B

题目分析：A、用适量石灰水检验并除去氢氧化钠中混有的少量碳酸钠，发生反应：Ca(OH)₂+Na₂CO₃==CaCO₃↓+2NaOH，正确，B、因为二氧化碳既不燃烧也不支持燃烧，所以用燃烧的方法不能除去二氧化碳中混有的少量一氧化碳，错误，C、硝酸铵固体溶于水吸热，使温度降低，氢氧化钠固体溶于水放热，使温度升高，所以可用水鉴别硝酸铵固体和氢氧化钠固体，正确，D、加过量的稀盐酸除去铜粉中混有的少量铁粉，铁会与盐酸反应，而铜不会，正确，故选B

完形填空

Christmas roses
It was the afternoon of December 24, the day before Christmas, and as the newest doctor in our office, I 36 to wok. The only thing that brightened my day was the beautifully 37 Christmas tree in our waiting room and a gift sent to me by my 38 --- a dozen red roses.
Then a woman came in with an infant (婴儿).39 she explained that her husband was a prisoner and was my next 40 . She told me she wasn’t allowed to visit her husband in prison and that he had never seen his son. She 41 me to let the boy’s father sit in the waiting room with her as long as possible 42 I called him for his appointment. Since my schedule wasn’t full, I 43 .
A short time later, her husband 44 ---with two armed 45 as an escort ( 护卫 ). The woman’s tired face 46 up like our little Christmas tree when her husband took a 47 beside her. I kept peeking out to watch them laugh, cry and 48 with their child.
After almost an hour, I called the 49 back to the operatory. The patient seemed like a gentle and humble（谦逊的）man. I wondered what he possibly could have done to be 50 under such conditions. I tried to make him as comfortable as possible.
At the end I wished him a Merry Christmas --- a difficult thing to say to a man 51 back to prison. He smiled and thanked me. He said he felt 52 by the fact he hadn’t been able to get his wife anything for Christmas. On 53 this , I was inspired with a wonderful idea.
I’ll never forget the look on both their faces as the prisoner gave his wife the beautiful 54 . I’m not sure who 55 the most joy --- the husband in giving, the wife in receiving, or myself in having the opportunity to share in this special moment.

D．possessions

C．remembering

D．experienced

填空题

西蒙并不否认个人价值和动机的重要性，相反，他把这些考虑归入______，即影响加入组织的决定的决定，而不是使个人同意加入的决定的决定。