删除；把多余的词 用斜线（ ）划掉。
The other day after work, I was walking down the street while I saw a boy riding a nice unicycle, one of those bicycle with only one wheel. Dressing in all pink from head to toe, he was singing a song which was sounded like a kid’s song. I thought he must be total crazy. Just then, a lady dropped 20-dollar bill on the ground, but he didn’t realize it and started to walk away. The guy in pink picked out the money and gave it back to her. After that, he rode on but soon disappeared before the lady could thank him. How a strange and good guy!
第一行：while改为when：was/were doing sth when … 是固定搭配；
第六行：How改为what，固定句型：what a/an adj+可数名词单数=How adj a/an 可数名词单数。
Union is strength. Whenever you're faced with difficulties or in a dilemma ,cooperation plays an important part in getting you out of trouble
There was a time when I was too proud that I overlooked my classmate, refusing to work together with them．Therefore , it was no doubt that I was left alone, suffering from loneliness and failure. Unfortunately a teacher impressed on me the value of cooperation. From then on , I learned to help others and turn to my friends for the help whenever I had difficulty finish a task on my own. Surely cooperation made a great difference. Now I am getting well with my friend．
My experience has teach me that only if we attach great importance with cooperation, can we go beyond ourselves. As the saying go "United we stand ;divided we fall．"