used to refer to a period of time or an experience during which you are awake清醒的;醒着的
Children are in school for 15 percent of their waking hours/life between birth and the age of 16.儿童从出生到16岁,不睡觉时有15%的时间在上学。
She seems to spend every waking moment/minute/hour (= all her available time) at the piano.她似乎把除睡觉以外的所有时间都花在钢琴上了。