一些细心的家长不难发现,当孩子升入中学以后,繁重的学习任务和业余爱好的增多会使得孩子的睡眠时间越来越少。最近美国科学家所做的一项研究表明,睡眠不足不但会影响孩子的自信心,而且还会使孩子出现忧郁情绪。研究人员对在美国伊利诺伊州就读的2259名中学生进行了调查。通过对这些学生的学习成绩、每天晚上的睡 Some attentive parents find it easy to find that when their children move to secondary school, heavy learning tasks and increased hobbies make them sleep less and less. A recent study by U.S. scientists showed that lack of sleep not only affects children’s self-confidence, but also makes them feel depressed. The researchers conducted a survey of 2,259 high school students enrolled in Illinois, USA. Through the academic performance of these students, sleep every night