neglects,loses 和 is是并列的.写成三句分别是：Who neglects learning in his youth?
Who loses the past Who is dead for the future?
主语从句和谓语之间有逗号是什么原因?比如这个句子
neglects,loses 和 is是并列的.写成三句分别是：Who neglects learning in his youth?
Who loses the past Who is dead for the future?