题干

下列变化过程不属于金属冶炼的是(  )


A:电解氧化铝

B:铁在氧气中燃烧

C:金属氧化物与焦炭在高温下反应

D:高温下CO还原CuO

上一题 下一题 0.0难度 选择题 更新时间:2019-05-12 11:01:28

答案(点此获取答案解析)

B

同类题1

阅读材料,回答问题

材料一:中国戏曲种类极为丰富,应普遍地加以采用、改造与发展,鼓励各种戏曲形式的自由竞赛,促成戏曲艺术的“百花齐放”。地方戏尤其是民间小戏,形式较简单活泼,容易反映现代生活,并且也容易为群众接受,应特别加以重视。今后各地戏曲改进工作应以对当地群众影响最大的剧种为主要改革与发展对象。

——周恩来《政务院关于戏曲改革工作的指示》(1951年5月5日)

材料二:1953年,郭沫若与范文澜在中国古代史分期问题上有不同意见,当时任中国历史问题研究委员会主任的陈伯达就此向***请示,***表示要“百家争鸣”。

材料三:“百花齐放,百家争鸣,”我看这应该成为我们的方针。艺术问题上百花齐放,学术问题上百家争鸣。“百花齐放”是群众中间提出来的,不晓得是谁提出来的。人们要我写字,我就写了这两句话:“百花齐放,推陈出新。”“百家争鸣”,这是两千年以前的事实,春秋战国时代,百家争鸣。讲学术,这种学术也可以讲,那种学术也可以讲,不要拿一种学术压倒一切。你如果是真理,信的人势必就会越多。

──***1956年4月28日在中共中央政治局扩大会议上的讲话

材料四:百花齐放,百家争鸣,长期共存,互相监督,这几个口号是怎样提出来的呢?它是根据中国的具体情况提出来的,是在承认社会主义社会仍然存在着各种矛盾的基础上提出来的,是在国家需要迅速发展经济和文化的迫切要求上提出来的。百花齐放、百家争鸣的方针,是促进艺术发展和科学进步的方针,是促进我国的社会主义文化繁荣的方针。艺术上不同的形式和风格可以自由发展,科学上不同的学派可以自由争论。利用行政力量,强制推行一种风格,一种学派,禁止另一种风格,另一种学派,我们认为会有害于艺术和科学的发展。艺术和科学中的是非问题,应当通过艺术界科学界的自由讨论去解决,通过艺术和科学的实践去解决,而不应当采取简单的方法去解决。

——***《关于正确处理人民内部矛盾的问题》(1957年)

同类题3

阅读下面的短文,从短文后各题所给的四个选项(A、B、C和D)中,选出可以填入空白处的最佳选项,并在答题卡上将该项涂黑。

A Welcome Gift

    Dario and his mother loved their new apartment. The living room was large enough for their piano. That night, the two of them 1 side by side at the piano. They played jazz music to celebrate their new home. The loud 2 filled the room and made them feel very happy.

    The next morning, 3, their happiness disappeared. Someone had left a 4 under their door during the night. One of their neighbor had written to complain(抱怨) about the sound of the piano. Dario's mother asked the building superintendent(管理员) if he knew anything about it. But he said that they were all 5 people and he couldn't imagine any of them had done that. Later that morning, Dario suggested that they write a letter to their 6 and apologize for their playing.

    “Maybe we could go and 7 everyone in person.” his mother said. “What if we invited them to come here for a 8 instead? Dario asked. They both loved the 9. Over the next few days, they sent out invitations and prepared desserts 10 their guests. They decorated the apartment with streamers(彩带) and party lights.

    Finally, the day of the party 11. Some guests brought presents. Others brought flowers. Some even brought desserts to 12. One woman, Mrs. Gilbert, 13 Dario's mother with a book of piano music by Chopin.

    “I heard you playing the other night,” she said. “The sounds woke me out of bed. I 14 that you might play like this every night. So I wrote a short note. I hope you don't think I disliked the playing.”

    Dario's mother smiled at Mrs. Gilbert. “I think maybe we 15 you an apology.” she said. “I didn't 16 how late it was when we were playing. Maybe we should play some quieter music at night.

    “You play, you play!” Mrs. Gilbert said. “I like what you play! Just not so loud at night.” She pointed to the book she had given them. “These songs are not such 17 music.”

    “These songs are beautiful music.” Dario's mother said. “We will be 18 to play them in the evening.”

    “And we won't play so loud or late!” Dario said. He was already looking forward to 19 the new music. More than that, however, he was happy to see the big smile on his mother's face. It gave him a feeling of 20 and made him feel that they were home at last.