You may know about “junk food” like French fries.But do you know about “junk sleep”？

    Recently, a British survey found that electronic(电子的) products in teenagers' bedrooms are affecting(影响) their sleep.

    The survey was done among 1，000 British kids from 12 to 16.It found that 30% of them got just 4 to 7 hours of sleep every day.But doctors say they need 8 to 9 hours.

    Almost a quarter of the kids said they fell asleep more than once a week while watching TV, listening to music or using other electronic products.

    “This is very worrying，” said Dr.Chris Idzikowski，a British expert，“We call it 'junk sleep'．It means you don't get enough sleep and the quality of the sleep is bad, too.If you don't get a good rest，you don't perform well in school the next day.”

    The survey found that 40% of the kids felt tired each day，with girls between 13 and 16 feeling the worst.Nearly all the teenagers have a cellphone，an iPad or a TV in their bedrooms.And many of them have all the three.

    One night four college kids____ (stay) out late, partying and having a good time. They paid no mind____ the test they had scheduled for the next day and didn't study.In the morning,they hatched a plan to get out of____ (take) their test.They covered____ (they) with grease（润滑油）and dirt and went to the Dean's office____ (nervous).Once there, they said they____ (be) to a wedding the previous night and on the way back they got____ flat tire and had to push the car back to campus.

    The Dean listened to their sad story and got lost in deep____ (think).Then he offered them a retest three days later.They thanked him and accepted his offer.

    ____ the test day arrived, they went to the Dean.The Dean put them ail in separate____ (room) for the test.They were fine with this since they had all studied hard.Then they saw the test.It had 2 questions.