My brother fell while he was riding his bicycle and hurt himself这句话有问题吗

题目

My brother fell while he was riding his bicycle and hurt himself这句话有问题吗
根据这个句子的形式不应该是 主句（过去式）+when/while+从句（过去进行时）吗,那为什么句中为hurt,不应该是hurting吗

答案

这个句子的主干是这样的： My brother fell and hurt himself. and前后都是过去时, fell和 hurt是并列谓语. 而从句while he was riding his bicycle是前面my brother fell的时间状语从句.