1 . If you’ve ever had trouble getting your teen up in the morning or you’ve seen your teen fall asleep during the school day, you’re not alone. Many teens have difficulty in waking up early for school, and that’s because they sleep late at night.

The American Academy of Pediatrics’ Adolescent Sleep Working Group reviewed studies about sleep in teens. Researchers studied the harmful effects of not getting enough sleep-anything less than 8.5 to 9 hours of sleep on school nights-could have on young people. They discovered not getting enough sleep may cause poor grades at school. Not getting enough sleep has also been connected to a higher risk of car accidents in teens.

It may seem as though the way to solve the problem would be for teens to just go to sleep earlier. But researchers say that isn’t likely to work. Teens experience physical changes that make falling asleep earlier difficult. Their biological (生物的) clocks just won't allow them to fall asleep at 8 p.m., even when they’re tired.

Studies have shown that just delaying (推迟) school by 30 minutes can have a great effect on a teen's health and performance. So most researchers suggest the school start time be delayed until at least 8:30 a.m. for teenagers.

Some of the benefits could include:

·Teens may be more likely to get the necessary amount of sleep.

·The delayed start time could help teens sleep during their natural sleep.

·Teens may be less likely to depend on coffee to stay awake during the day.

·Enough sleep could help teens study better in class, which could help them do better in exams.

·Sleeping longer could reduce health problems caused by a lack of sleep in the long run.

·Getting home later in the afternoon may reduce the amount of time when some teens are home alone, and could reduce the possibility that tens will take part in unhealthy activities.

But doing that can also cause some problems.

1. What does Paragraph 1 show?

A．Many teens find school too boring.

B．Many teens fail to get enough sleep.

C．Today’s teens have many difficulties.

D．Today’s teens are too lazy to get up early.

2. What do researchers of the Adolescent Sleep Working Group find?

A．Today’s teens have poor grades at school.

B．Teens should get at least 8.5 hours of sleep daily.

C．Today’s teens are in danger because of car accidents.

D．Teens can be negatively influenced by not getting enough sleep.

3. Why can’t teens fall asleep earlier?

A．Because their homework is too much,

B．Because they love staying up late at night.

C．Because their physical changes make it hard.

D．Because they have unbalanced biological clocks.

4. What would the text most probably talk about next?

A．The disadvantages of starting school later.

B．The benefits of getting enough sleep for students.

C．The methods of helping students get enough sleep.

D．The advantages of putting off the school start time.