我在写英语文章时这样写:After listening the doctor's words, Xiao Ming nodded and said:"OK.Doctor, I'll pay more attention next time while I'm playing football."(节选)但老师说我写after listening有错!我真想不明白是为什么?P.S.这是整篇文章要求用的时态为一般过去时。如果我真的错了, 那我应该怎么改正呢?