preface a speech 演讲前做序
preface with something 以...为开场
preface a book 为书作序
A: Why is he prefacing the meeting with such a long joke?
A：他为什么要用这么长的笑话来给会议开场？
B: He is prefacing it to lighten the atmosphere.
B：他是在通过这种方式活跃气氛。
1) 为...作序
2) 在...之前进行铺垫
3) 作为...的前言
1. 为...作序；在...之前做铺垫
verb
1. To introduce something by a preliminary statement or a preface.
Synonym: introduce, prelude