首先要明确无论是concerning还是regarding都不和about连用。接下来看看二者分别的含义:
concerning
1. )PREP 关于 You use concerning to indicate what a question or piece of information is about.
For more information concerning the club contact I. Coldwell.
咨询俱乐部详情,请与I.科德维尔联系。
...various questions concerning pollution and the environment.
有关污染和环境的各种问题
2. )ADJ 让人不安的;令人担忧的 If something is concerning, it causes you to feel concerned about it.
It is particularly concerning that he is working for non-British companies while advising on foreign policy.
让人尤为不安的是,他在提供外交政策咨询的同时却又供职于一些外国公司。
regarding
1. PREP 关于;至于 You can use regarding to indicate the subject that is being talked or written about.
He refused to divulge any information regarding the man's whereabouts.
关于那个人的行踪他拒绝透露任何信息。
二者字面上在“关于”这个意思上是没有区别的,当然中国人最喜欢的就是找区别,非要从concern和regard本身出发去辨别,实际上两个词是完全interchangeble的,我在google英文版本搜了很久二者的区别,它们的回答基本上是一致的,那就是没有区别,如果你非要理解个区别出来,那好吧,你就按照他们俩本意理解,concerning偏重关心,regarding真的没什么偏重就是客观的关于,什么决策的在字典例句里根本体现不出来