enroll on６ 例句 Very little is written about this subject in most aromatherapy books, so unless you enroll on a training course knowing how to select them can seem like a bit of a black art. 绝大部分芳疗书中对于这个问题的介绍都是一笔带过，所以除非您参加专业的培训课程，否则如何选择基础油会像魔术一样难以捉摸。31931