把这篇文章中的所有现在完美时态改为简单过去时。


John has been studying in this school for three years. During his time here, he has taken many courses and has made a lot of friends. He has also participated in several extracurricular activities, such as the school's debate club and the chess club.
John studied in this school for three years. During his time here, he took many courses and made a lot of friends. He also participated in several extracurricular activities, such as the school's debate club and the chess club.