问题描述：
帮忙解释一下这句的结构
原句：perhaps most challenging is the set of skills required to produce a written assignment,the most common means by which student learning is evaluated.
请问逗号以后的部分与前句是什么结构关系啊?并请翻译一下,谢谢!
原句：perhaps most challenging is the set of skills required to produce a written assignment,the most common means by which student learning is evaluated.
请问逗号以后的部分与前句是什么结构关系啊?并请翻译一下,谢谢!
问题解答：
我来补答展开全文阅读