Having failed many times,he regretted_ His parents advice(follow) 多次失败后,他后悔没听父母的建议.

Having failed many times,he regretted_ His parents advice(follow) 多次失败后,他后悔没听父母的建议.
Having failed many times,he regretted_ His parents advice(follow) 多次失败后,他后悔没听父母的建议.

Having failed many times,he regretted_ His parents advice(follow) 多次失败后,他后悔没听父母的建议.
following regret doing sth

应该是not to follow,根据句意应该是否定的形式
reget to do是遗憾未地(事情未做)
reget doing是遗憾的(做过某事)
希望能帮到你