(1)金属A和金属B用导线相连同时插入稀硫酸中，金属A逐渐溶解,金属B上产生大量气泡，则较活泼的是______ (填A或B)，正极反应式为：____________。
(2)以Cu和Ag为两电极，AgNO3溶液为电解质溶液构成原电池。原电池工作过程中，正极和负极质量改变量之比为______________ （已知Cu和Ag的相对原子质量分别为64和108）。
(1)A；2H++2e－=H2↑
(2)27︰8
Studying Abroad Nowadays, studying abroad gains popularity in China. Many rich parents would rather send their children abroad to receive education than let them be educated in China. As every coin has two sides, studying abroad is not an exception. There are advantages for people to attend school abroad. In the first place, he can use the foreign language in his daily life so that his ability in the second language may be greatly improved, as it is obvious that there is no better chance to improve second-language than living in the country where it is spoken. While studying in a foreign country, he will most likely meet many others from overseas and it is possible to make friends from all over the world. This is not only exciting on the social level, but could lead to important overseas contacts in his career as well. He can get familiar with the latest knowledge in science and make use of the first-rate facilities (设备) available. In this way, there is every chance that he is able to widen his horizon (眼界) and broaden his mind. Of course, attending schools abroad may bring about a series of problems. The most serious problem is language barrier (障碍). Most of the students who go abroad don’t have enough skills in the language spoken there. As a result, on arriving there, they will find it difficult to understand what the teachers say. Besides, for lack of knowledge of the customs of the local people, they may constantly run into trouble in dealing with various situations. Therefore, given an opportunity to attend a school abroad, one must consider both sides of the factors carefully before making up his mind.
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