unprotected sleep 回笼觉

wake up naturally without alarm clock 自然醒

have a cat nap 打个小盹

doze off 打瞌睡

have a siesta 午睡

do not sleep a wink 一夜没合眼

hit the sack 倒头就睡

light sleeper 睡觉轻的人

sleep around the clock 睡了一整天

caught napping 毫无准备，措手不及