题干

下列实验中,对应的现象以及结论都正确且两者具有因果关系的是(   )

实验

现象

结论

A

将氯气通入品红溶液

溶液红色褪去

氯气具有漂白性

B

将铜粉加入1.0mol•L﹣1

的Fe2(SO4)3溶液中

溶液变蓝,有黑色固体出现

金属Fe比Cu活泼

C

用坩埚钳夹住用砂纸仔细打磨过的铝箔在酒精灯上加热

熔化后的液态铝滴落下来

金属铝的熔点比较低

D

向盛有少量浓硝酸、稀硝酸的两支试管中分别加入一片大小相同的铜片

浓硝酸中铜片很快开始溶解,并放出红棕色气体;稀硝酸中过一会铜片表面才出现无色气体,气体遇空气变红棕色

浓硝酸氧化性强于稀硝酸

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:2019-11-15 03:49:39

答案(点此获取答案解析)

D

同类题1

阅读余敏之的《植物也能跟人“对话”了》一文,完成后面小题。

       ①早有科学研究表明,植物间是可以相互对话的——它们通过向空气中释放化学信息与周围“同伴”交流,内容包括提醒“同伴”害虫入侵的警示,或是“讨论”周围出现的蜜蜂等传粉昆虫信息。

       ②为了让人类能直接参与到与植物的对话之中,科学家一直在寻找一种最有效的方式,2016年6月3日,人类终于能借助微软研发出的软件“Florence计划”,实现了人与植物之间的“对话”!

       ③这种软件“Florence计划”是通过微软的Surface平板电脑和Azure云服务平台实现的,他们所选择的植物是自然界中极其常见的风信子。研究开始时,成员之一的海伦将风信子放入适合植物生长的装置中,又将该装置与电脑相连,然后输入想要表达的信息。这时,Azure云服务平台就使用自然语言处理技术分析刚刚输入的文字,并将其转换为光学信号。通过这种方式向风信子传递情感;传感器也将收集到一系列风信子“思考”的依据,从中了解风信子对人类感情的回应。

       ④最后,根据与风信子底部相连接的一台小型打印机所发出的信息,研究者把它翻译出来,就能看到风信子的“回复”了。而研究者通过研究那些“回复”,能明确感知当风信子处于困境时,它就会释放出一种挥发性有机化学物VOC,来提醒周边的风信子危险正在靠近。

       ⑤而当人类跟它们沟通时,它们会利用Azure云服务“回复”一两句话。那些话是从打印机上收集来的,与我们此前输入的文字具备极其相似的语境。有意思的是,风信子回复的内容还会带有一些受它“心情”影响的情绪。

       ⑥请看下面研究人员翻译出的海伦与它的对话:

       海伦:你好。

       风信子:嗯,你好。

       海伦:你感觉如何?

       风信子:很好,我很高兴。

       海伦:你太棒了!

       风信子:谢谢,你也很棒!

       ……

       海伦:再见。

       风信子:再见,看到你真高兴!

       ⑦当然,风信子只是人类与自然连接互动的第一个实例,“Florence计划”领导者海琳·斯坦纳希望今后不仅能阅读植物的传感器信号,还能发送信号并刺激植物内部交流,这样我们就能帮助植物以更自然的方式适应这个世界。”

                                                                                                                                                             (选自《知识窗》2016年第9期,有删改)

同类题2



    Happiness is important for everyone. Most people want to be happy but few know how to find happiness. Money and success don't bring lasting happiness. Happiness depends on ourselves. In other words, we make our own happiness.
    Some people believe that if they are wealthy, with the money they will be able to do anything they want, which means happiness. On the other hand, some people believe that holding a high position in the government is happiness. In this way, you have not only money, but also many other things which can't be bought by money. However, other people believe that having lots of money is not happiness, nor is holding a high position in the government. These people value(重视) their beliefs, or their intelligence, or their health. They think these can make them happy.
    Here are a few ways to help you be happier.
    The first secret of happiness is to enjoy the simple things in life. Too often, we spend so much time thinking about the future, for example, getting into college or getting a good job, that we don't enjoy the present. You should enjoy life's simple pleasures, such as reading a good book, listening to your favorite music, or spending time with close friends. People who have close friends usually enjoy happier and healthier lives.
    The second secret of happiness is to be active. Many people go dancing or play sports. People can forget about their problems and only think about the activities.
    Finally, many people find happiness in helping others. According to studies, people feel good when they volunteer their time to do many meaningful things for other people. If you want to feel happier, do something nice for someone. You can help a friend with his or her studies, go shopping to get food for an old neighbor, or simply help around the house.
    Now maybe you know how to find happiness!