A. They are all based on real stories.
B. They are all inspiring stories that make a difference.
C. The main characters all won Academy Award for best actor.
D. The main characters are sick to some degree but succeed.
D
For many of us, a little time with our smartphones or iPads before sleep is the highlight of the night. But would you still think it is relaxing if you knew that it damages or destroys your sleep? Scientists say that’s exactly what it does.
In ancient times, when there were no lamps, telephones or smartphones, the sun was the main source of light. When the sun went down, our brains took that as a signal to start producing melatonin(褪黑素), a chemical that helps us sleep.
However, a healthy amount of melatonin can only be produced in complete darkness. Any light in your bedroom — even the one on the alarm clock or the charging indicator on your cellphone — could disturb the process, not to mention something as bright as smartphone and iPad screens. We tend to hold these much closer than a television or a laptop, which allows them to shoot far more light straight into our eyes.
“This is particularly worrisome in populations such as young adults and adolescents, who already tend to be night owls,” said researcher Brittany Wood at Rensselaer Polytechnic Institute. “Lack of sleep among teens is leading to depression, selfharm, low concentration and poor performance at school,” she added.
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