You can describe an event as a prelude to a more important event when it happens before it and acts as an introduction to it.
例句
Most unions see privatisation as an inevitable prelude to job losses...大多数工会认为私有化会不可避免地导致失业。The conference, which closed yesterday, was a prelude to a Communist Party Central Committee meeting.昨天结束的会议拉开了共产党中央委员会会议的序幕。
N-COUNT
序曲;前奏曲
A prelude is a short piece of music for the piano or organ.
例句
...the famous E minor prelude of Chopin.肖邦著名的E小调前奏曲
英汉词典释义
n.
开端, 序幕, 前奏
The discussions were a prelude to the treaty.这些讨论是签订该条约的前奏。
序曲
The prelude to the musical composition is very long.这首乐曲的序曲很长。
英英词典释义
Noun
1. something that serves as a preceding event or introduces what follows;
"training is a necessary preliminary to employment""drinks were the overture to dinner"
2. music that precedes a fugue or introduces an act in an opera