If you are a sleep deprived  teacher, you may not be aware of the term woodpeckering , but you've probably done it. It happens the day following a bad night's sleep. You're sitting in a long meeting and you can barely keep your eyes open, so you support your head up with your hand. Next thing you know, you are moving your sleeping head back to its upright position. Do this a few times and you are woodpeckering. I thought I knew sleep deprivation when I did my medical internship  in hospital. That year I frequently went 36 hours with no sleep. When I finished my stay in neurology , I welcomed the promise of full nights of sleep ever after. It went pretty well for the next 10 years until I became a school teacher and experienced a whole new level of sleep deprivation. Teachers' working hours go far beyond the 8 am to 5 pm schedule of kids in school. There are hours spent at staff meetings, correcting homework, preparing for the next day- and then there is the worrying. What I did in a hospital emergency room required no more intensive mental energy than what is need to keep 30 kids attentive enough to learn what I was teacher. Good teachers are like magicians keeping a dozen balls in the air to come at right time, with alarm set for 6 am to finish grading papers, memories of the day that's gone- including the students who didn't understand something, forgot their lunch or were embarrassed by wrong answers. All these will become sleep-resistant barriers. And also with some financial stress, you'll have a cycle of insomnia  with unwelcome consequences. With inadequate sleep comes irritability , forgetfulness, lower tolerance of even minor annoyances, and less efficient organization and planning. These are the very mental useless that teachers need to meet the challenges of the next day. In wanting to do a better job the next day, the brain keeps bringing up the worries that deny the rest it needs. The writer's new level of sleep deprivation began since he   _  .
did his medical internship in hospital began to teach in a school left hospital ten years ago went 36 hours with no sleep
Question: If you are a sleep deprived  teacher, you may not be aware of the term woodpeckering , but you've probably done it. It happens the day following a bad night's sleep. You're sitting in a long meeting and you can barely keep your eyes open, so you support your head up with your hand. Next thing you know, you are moving your sleeping head back to its upright position. Do this a few times and you are woodpeckering. I thought I knew sleep deprivation when I did my medical internship  in hospital. That year I frequently went 36 hours with no sleep. When I finished my stay in neurology , I welcomed the promise of full nights of sleep ever after. It went pretty well for the next 10 years until I became a school teacher and experienced a whole new level of sleep deprivation. Teachers' working hours go far beyond the 8 am to 5 pm schedule of kids in school. There are hours spent at staff meetings, correcting homework, preparing for the next day- and then there is the worrying. What I did in a hospital emergency room required no more intensive mental energy than what is need to keep 30 kids attentive enough to learn what I was teacher. Good teachers are like magicians keeping a dozen balls in the air to come at right time, with alarm set for 6 am to finish grading papers, memories of the day that's gone- including the students who didn't understand something, forgot their lunch or were embarrassed by wrong answers. All these will become sleep-resistant barriers. And also with some financial stress, you'll have a cycle of insomnia  with unwelcome consequences. With inadequate sleep comes irritability , forgetfulness, lower tolerance of even minor annoyances, and less efficient organization and planning. These are the very mental useless that teachers need to meet the challenges of the next day. In wanting to do a better job the next day, the brain keeps bringing up the worries that deny the rest it needs. The writer's new level of sleep deprivation began since he   _  .
A. did his medical internship in hospital
B. began to teach in a school
C. left hospital ten years ago
D. went 36 hours with no sleep
Answer: