求人帮我改改这个英语的段子,改错变通顺啊!急.

I am 23 years old,there is one thing that I will never forget since a long time ago.In the third year of my college study,two of my schoolmates and I signed up(报名) to take part in a national math model competition.School Leaderships paid so much attentions to the competition.In accordance with the rules for the competition,we had to finish an independent panel finishing topic in one week time .In order to avoid outside influence we placed designated rooms,in that period of time we were almost isolated from the world outside.The only existence in our minds was the idea that try to make the subject well.That period of time was extremely unendurable,because there are too many of the topic data.We could only divide into the data certain then independently made the processing.Data laws was not easy to find,among 5000 data,we repeated projections and verification,every time with the hope to prove it hard.However,the failure of a meeting came,we became discouraged,or even despaired.During that time,I understood what's a team,and how the team helped each other,encouraged each other to complete the common objective.Although we did not get in the final top rank,I felt that I learned a lot of things from it,that seven days were a rich experience of joy for me.This make it most difficult for me to forget that thing.
已帮你改完,只提醒你一句话,如果以回忆的方式写,那么除了前后呼应的表示现在的话用现在时,中间关于那次考试的过程要全部用过去时态!

am 23 years old, during the long time,there was one thing that I will never forget . In the third year of college, my two schoolmates and I registered together to attend the national math ematical mod...

I am 23 years old, and during my long life,there is one thing that I will never forget. In my third year of college, my two schoolmates and I registered together to attend the national mathematical mo...

I am 23 years old, during the long time,there was one thing that I will never forget . when I was Junior, I registered together with my two schoolmates to take part in the national math ematical model...