Spring really is 'spring sleep, unaware of dawn' - even the alarm can't wake me.
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Opening line of Meng Haoran 孟浩然的《春晓》 (Tang): 春眠不觉晓,处处闻啼鸟。夜来风雨声,花落知多少。 (In spring I sleep past dawn; everywhere I hear birdsong. Through the night came wind and rain - how many blossoms have fallen, who knows?) One of the first poems Chinese children memorise.
usage
Used both literally (spring drowsiness) and figuratively (blissful obliviousness). 晓 (xiǎo) here = dawn, not 'know.'