单项选择题

Have you ever experienced tossing and turning (辗转反侧) in bed late at night while counting sheep Do you often rely on sleeping pills About one third of your life is spent asleep, but do you really enjoy good and healthy sleep Unfortunately, about one third of adults suffer from insomnia (失眠症). According to a recent survey taken of 10 000 Shanghai people, more than 70% of locals have sleep disorders of one kind or another. The results show that about 36.5% of interviewees don’t have good sleep; 45.3% wake up very early in the morning and 54.3% feel sleepy during the day. Without drink or food, one can survive for 7 days; but without sleep, one can only last 4 days. Babies sleep for at least 16 hours a day because their brains and bodies develop faster during sleep. After that, the sleep period gets shorter. Beyond the age of 10, most people need fewer than 10 hours sleep a night. For the elderly, 6 or 7 hours is usually enough. High-quality and sufficient sleep ensures an energetic physical condition and a good mental outlook. But bad or inadequate (不充足的) sleep has a negative influence on one’s health and quality of life.

The author writes this passage so as to inform you of （）

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