假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。
增加：在缺词处打一个漏字符号（ ʌ）,并在其下面写出该加的词。
删除：把多余的词用斜线（\）划掉。
修改：在错的词下划一横线，并在该词下面写出修改后的词。
注意：1 每处错误及其修改均仅限一词；
2. 只允许修改10处，多者（从第11处起）不计分。
The story of why I learnt to swim is interesting. Three years before, my father and I went for swim. While my father was changing his clothes, I am walking along the side of the pool. Suddenly I slipped into the pool. I was too afraid that I shouted at once. The water kept come towards me. Although I was afraid, but I struggled very hard to keep my head above the water. In my surprise, I was able to keep doing it. Just then, my father saw me and said, “Calm down. Just wave your arm and legs like this. Right !” And I got it. I final learnt to swim.