It is reported that many middle school students are just not getting enough sleep, especially during the school week. The problem seems to get worse as they get older. Grade 7 students sleep 8.4 hours a school night, and Grade 9 students only 6.9 hours.
（3） It’s also reported that not getting enough sleep can cause problems in a student’s life. Many students fall asleep in school or while doing their homework, so it is not surprising that they get lower grades than those who get enough sleep.
Scientists suggest nine hours a night for middle school students. Of the students who feel unhappy and nervous, 73% don’t get enough sleep at night. Why aren’t students getting enough sleep? Many students have one of the following things, like telephone, television, or computer in their bedrooms. Using them on a school night not only takes their time away from homework, but also makes it difficult for them to fall asleep. （4） As a result, many students can't fall asleep before 11 pm, yet they must get up early to go to school the next day .
Scientists also suggest students should not do exciting activities for an hour before bedtime.
（一）根据短文内容简要回答问题。
1. How many hours of sleep do middle school students need each night according to the scientists?
2. What shouldn’t students do before bedtime?
（二）将短文中划线的句子译成汉语。
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4.
（三）请给短文拟一个适当的标题。
5.