C
Teenagers need eight to ten hours of sleep per night. However, in adolescence(青春期), changes to the body's sleep cycle make it difficult for teens to fall asleep early. Many cannot fall asleep until 10:30 p. m. or even later and most of them will feel sleepy if they have to get up too early.
Scientists recommend that both middle and high schools begin no earlier than 8:30 a. m. Later school start times support the natural needs of teenagers and increase their sleeping time.
Here are some other benefits(益处) of later school start times:
• More time for a healthy breakfast
When running late in the mornings, students are likely to go without breakfast. With an empty stomach, one finds it difficult to focus in class. When they are always in a hurry, students may form unhealthy eating habits.
With extra time before going to school, students can eat a well-balanced breakfast and focus more on learning.
• Fewer behavioural problems(行为问题)
Teens experience mood changes as a common result of this special period of life. Less sleep may cause worries, stress and unhappiness.
When they get enough sleep, students are calm and peaceful and their moods do not change suddenly. They're less likely to feel worried, unhappy or angry. For parents, children with more sleep are easier to live with.
• Better performance(表现) in study
Sleep loss hurts attention, memory and brain development. Students with less sleep have difficulty paying attention in class and are likely to have lower grades. Students with enough sleep can be more energetic during the day and more willing to learn. They are also less likely to fall asleep in class and can better understand what they learn.
In conclusion, starting school later helps students get a better night's sleep. It improves their eating habits, behaviour and performance.
()33. According to the passage, what may cause teenagers to stay up?
A. Their low grades.
B. Their empty stomachs.
C. Their body's sleep cycle.
D. Their heavy homework.
()34. How can sleep loss influence students' study?
A. It gives them much energy.
B. It does harm to the brain.
C. It saves more time for study.
D. It improves their memory.
()35. What's the writer's main purpose in writing this passage?
A. To explain reasons for students' stress.
B. To describe bad habits caused by sleep loss.
C. To discuss scientists' research on healthy food.
D. To introduce benefits of later school start times.
()36. In which part of the website can you probably find this passage?
A. Education.
B. Fashion.
C. Sports.
D. Technology.