题干

欲除去下列物质中的少量杂质,所用试剂及方法错误的是(   )

序号

混合物

除杂试剂与方法

A

氧气中混有少量水蒸气

通过浓硫酸干燥

B

氯化钾溶液中混有少量的碳酸钾

加入适量氯化钙溶液,过滤

C

二氧化碳中混有少量一氧化碳

通过灼热的氧化铜

D

氧化钙中混有少量碳酸钙 

加水溶解,过滤

A:A   

B:B   

C:C   

D:D

上一题 下一题 0.0难度 选择题 更新时间:2018-05-30 09:28:14

答案(点此获取答案解析)

D

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任务型阅读

阅读下列短文,根据短文中的信息完成文后表格。在答题卡标有题号的横线上,写出空缺处所填单词的正确形式。(每空一词)

    Many people think dreams are full of messages that may not be clear to us common people. But if we think about what is going on in our lives, we can usually come up with an answer. Let's look at some of the most common dreams. What are the meanings of these dreams?

    Falling

    You're falling, falling, falling… and then you wake up. This dream is said to mean you are in fear of something or worried about something. There may be something in your life that is out of control and there is nothing you can do to stop it. Another explanation is that you may experience failure in something. Maybe you're not doing well in school or work.

    Taking an exam (or forgetting that you have one)

    You suddenly realize you have to take an exam at that very moment. You might be running here and there to find your classroom. Scientists say this dream may mean you're being tested about something or maybe you are facing a challenge.

    Flying

    Dreaming that you are flying means you are on top of things. You are in control of the things that matter to you. It may also mean you have confidence in yourself and think no one and nothing can beat you.

    Trying to run, but going nowhere

    You're trying to run, but either of your legs won't move or you simply aren't going anywhere. Some scientists think this dream means you're trying to do too many things at once and can't catch up or move forward.

    In fact, unlike these dreams, there are also many strange dreams that scientists may not be able to explain.

Title: What do dreams ____?

Descriptions of dreams

Answers to dreams

Falling

*You have something to be ____of or worry about.

*You may ____ in something like schooling or work.

Taking an exam

(or forgetting that you have one)

* Maybe you're taking part in a ____ .

* You may face something ____ .

Flying

*You're able to ____what matters to you.

*You believe in yourself and think that you can beat anyone and ____.

Trying to run, but going ____

*You're trying to do too many things at the same time and it prevents you from ____ forward.

Conclusion: Scientists can ____ some dreams, but not all the dreams.