help me me ENGLISH

While I (1)______(walk)home from school,I saw two bad teenagers who(2)___________(bully)a student at the dark corner of a street.The student(3)___________(use)to be my classmate.He (4)_________(study)in my class last year.He (5)_________(leave)us because he had violated school rules seriously.
When I saw the case,I(6)_________(report)it to the police immediately.The policemen(7)__________(arrive)at the scene quickly.They(8)____________(look)for the two bad guys(10)___________(be)very scared and ran as quickly as they could,but the policemen(11)__________(run)after them.Finally,the policeman(12)___________(catch)them and(13)__________(take)them to the police station for further investigation.
On the way to the police station,the two teenagers(14)_________(beg)the policemen to give them a chance.However,the policemen(15)____________(keep)silent while they(16)_________(take)the two teenagers to the police station.