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 回答下列与金属有关的问题

(1)在黄铜(铜锌合金)片和纯铜片中,硬度较大的是____,将它们分别放入稀盐酸中能产生气泡的是____

(2)铁生锈是铁与空气中的____发生化学反应的过程;

(3)向AgNO3和Cu(NO32的混合溶液中加入一定量Al粉,充分反应后过滤;取少量滤液滴加稀盐酸,产生白色沉淀.滤液中一定含有的溶质是____


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黄铜片,黄铜片,氧气、水,硝酸铜、硝酸银、硝酸铝

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   If you think English means endless new words, difficult grammar and sometimes strange pronunciation, you are wrong. Haven’t you noticed that you have become smarter since you started to learn a language?
   According to a new study by a British university, learning a second language can lead to an increase in your brain power. Researchers found that learning other languages changes grey matter. This is the area of the brain which processes information. It is similar to the way that exercise builds muscles.
   The researchers also found the effect is greater on the younger people who learn a second language.
   A team led by Dr. Andrea Mechelli, from University College London, took a group of Britons who only spoke English. They were compared with a group of “early bilinguals(通两种语言的人)”, who had learnt a second language before the age of five, as well as a number of later learners.
   Scans showed that grey matter density(密度)in the brain was greater in bilinguals than in people without___________________. But the longer a person waited before mastering a new language, the smaller the difference was.
   “Our findings suggest that the structure of the brain is changed by the experience of learning a second language,” said the scientists.
It means that the change itself increases the ability to learn.
   Professor Dylan Vaughan Jones of the University of Wales, has researched the link between bilingualism and maths skills. Having two languages gives you two windows on the world and makes the brain more flexible,” he said, “You are actually going beyond language and have a better understanding of different ideas.”