[解析]
Dear Peterson,
I am a 18﹣year﹣old middle school student, I have been busy with my study and seldom help my parents with housework. (高分句型一)Feeling very sorry for them, I begin to think about what to do to help. (做家务的理由)
(叙述做家务的过程)Last Sunday, when my parents went out shopping, (高分句型二)it suddenly occurred to me that I can give the rooms a thorough cleaning. Firstly I collected all the books, newspapers and other things scattered in the rooms and put them in place. Then I wiped the dust off all the furniture. After that, I swept and mopped the floors.
(我的感受)At that moment, my parents came back and were quite surprised to see all the rooms tidy and floors shining. My mother gave me a hug and I could see her satisfaction from her eyes. (高分句型三)Tired as I was, I felt so happy.