某校化学研究性学习小组欲设计实验验证Fe、Cu的金属活动性，他们提出了以下两种方案．请你帮助他们完成有关实验项目：

方案Ⅰ：有人提出将大小相等的铁片和铜片，分别同时放入稀硫酸或稀盐酸中，观察产生气泡的快慢，据此确定它们的活动性．该原理的离子方程式为____．

方案Ⅱ：有人利用Fe、Cu作电极设计成原电池，以确定它们的活动性．试在下面的方框内画出原电池装置图，标出原电池的电极材料和电解质溶液，____

并写出电极反应式．正极反应式：____；负极反应式：____；

方案Ⅲ：结合你所学的知识，帮助他们再设计一个验证Fe、Cu活动性的简单实验方案与方案Ⅰ、Ⅱ不能雷同：____，用离子方程式表示其反应原理：____．

根据短文内容及首字母提示，填入适当的单词，使短文的意思完整。（在填写答案时，单词的第一个字母要写出来）
    Have you ever seen Korean writing before? In many people's eyes, it  l____  lovely but difficult. Do you know the h____ of the special letters?
    Long ago, Korean people didn't  o____ their letters. At that time, they used Chinese characters(字符). Because Chinese is hard to learn, only rich people had the m____ and time to ask teachers to teach them. One of their kings was called Sejong. He decided to i____ Korean Letters. He thought hard.
    One day, on  O____  9, 1446, he looked at a window frame(框架)and shouted, “I know what our letters should be!” He was so excited that he cried it loudly. He got the i____from the frame and invented letters of all the same size. It seemed that they were put in a window frame. The  earliest Korean letters were born. King Sejong said, “Chinese characters can’t express Korean  meanings. Now I invent  o____  own letters. These letters are very  e____  to learn. I hope that they can help all people learn to read.”
    When King Sejong first invented the Korean letters, they had 28 letters, but only 24 are used today. All the Korean people enjoy  u____ their own letters. Some Chinese young people think they're interesting.