36-40 為題組    These days, teachers often face classrooms filled with yawning students who stayedup playing online games. For children and teens, using cell phones, tablets and computersat night is associated with losing sleep time and sleep quality. Researchers found a strongand consistent relationship between bedtime media device use and inadequate sleepquantity, poor sleep quality and excessive daytime sleepiness. A large-scale pollconducted in the United States by the National Sleep Foundation reported in 2013 that72% of all children and 89% of teens have at least one device in their sleep environment.Most of this technology is used near bedtime. This omnipresent technology negativelyinfluences children’s sleep by delaying their sleep time, as they finish watching a movieor play one more game.   Light emitted from these devices may also affect body temperature and hormonerelease. One specific hormone, melatonin, causes tiredness and contributes to the timingof our sleep-wake cycles. Electronic lights can delay the release of melatonin, disruptingthis cycle and making it harder to fall asleep. In addition, online content may bepsychologically stimulating and keep children and teens awake far past the hour whenthey turn off their devices and try to sleep.    Sleep plays a crucial role in a child’s healthy development, even though we do notknow all of the science behind it. Tips that help facilitate good sleep include having aroom that is quiet. Parents should remove items that interfere with sleep, includingelectronics, TV, and even pets if they interfere with sleep. One more important tip comesfrom the National Sleep Foundation, which recommends at least 30 minutes of “gadgetfree transition time” before bedtime.
36.What is this passage mainly about?
(A)How children loves online games.
(B) Suggestions for good sleeping quality.
(C)Why students fall asleep in the classroom.
(D)Electronic devices and children’s sleeping quality.