N-VAR
序文；导言；开场白
A preamble is an introduction that comes before something you say or write.
例句
The controversy has arisen over the text of the preamble to the unification treaty...
针对统一条约的序文出现了争论。
'I would like you to return to the villa as soon as possible,' she said without preamble.
她开门见山地说：“我想让你尽快回到别墅。”