a prelude to
preliminary prolusion
the prolusion of an event
A: Was the short speech a prolusion to the main ceremony?
A：那段简短的演讲是主仪式的序幕吗？
B: Yes, it was meant to introduce the theme of the day.
B：是的，它是为了介绍今天的主题。
1) 序曲
2) 准备工作
3) 开端
1. 序幕，准备
noun
1. A preliminary action or preparation for something; a prelude.
Synonym: prelude, preamble