完成
　　be done with sth.
　　be through with sth.
　　be finished with sth.
　　to complete sth.
　　to finish doing sth.
　　be over with sth.
　　be over and done with
　　end up
　　 累
　　原因：学习、运动、打工
　　表达：
　　I’m exhausted.
　　I’m tired-out/over tired.
　　I’m dog tired.
　　I’m beat/dead beat.
　　I’m burned out.
　　run out of steam/energy
　　be out of energy/shape
　　I’m worn out.
　　be tired out
　　knock oneself out on sth.
　　eyes are starting to blur
　　hardly stay awake
　　hardly concentrate
　　I’m bushed.
　　学生学习用功
　　around the clock
　　on end = in a row
　　day and night = night and day
　　36/48 hours a day
　　day in and day out
　　put a lot of hours/time/days into…
　　burn the midnight oil
　　stay up/be up all night
　　can’t tear oneself away from…
　　couldn’t put down…
　　glue one’s eyes to…