jump in at the deep end
从深水区开始，迅速投入到一项新的活动或情况中，而不事先做好准备
口语·形容被迫面对挑战
英文释义
to start a new and challenging task or situation without any prior experience or preparation
例句
I had no training for the job; they just threw me in at the deep end.
典故来源
源自游泳教学，初学者直接跳入深水区，比喻毫无准备就面对困难任务。