introductory
adjective uk/ˌɪn.trəˈdʌk.tər.i/ us/ˌɪn.trəˈdʌk.tər.i/
(FIRST TIME)
首次的（存在，使用或经历）
existing, used, or experienced for the first time
an introductory price/offer 试销价格／优惠
an introductory course in design (= a course for people who have not done it before) 设计入门课程
(BEGINNING)
引导的;序言的
written or said at the beginning
an introductory chapter 序篇
I'd like to make some introductory remarks before beginning the lecture. 我想在讲座正式开始之前说几句开场白。