adj.未经要求，未被邀请，擅自

The memories of the past unbidden came flooding back.
过去的记忆不由自主地涌上心头。
His help was unbidden but much appreciated.
他的帮助虽未被要求，但非常受感激。
She felt a sense of unease, unbidden and inexplicable.
她感到一种莫名的不安，不请自来。
Unbidden tears rolled down her cheeks.
泪水不自觉地滑落她的脸颊。
The unbidden thought kept recurring to his mind.
那个不请自来的念头在他的脑海中反复出现。
A smile unbidden curved his lips.
一个不自主的笑容浮现在他的嘴角。
The guest arrived unbidden, much to the host's surprise.
客人未经邀请突然到访，让主人颇为惊讶。
Her anger subsided, leaving only an unbidden sadness.
她的愤怒平息了，只留下一抹无法驱散的悲伤。
He heard an unbidden whisper in his ear.
他耳边响起了一个不请自来的低语。
The unbidden desire for adventure took hold of him.
对冒险的渴望不请自来，紧紧抓住了他。