Almost everyone feels sleepy sometimes during the daytime. Being sleepy may get in the way of your daily work，childcare，and even activities for fun. Here are some ways to improve nighttime sleep and avoid daytime sleepiness.
1．Get adequate nighttime sleep.
That may sound obvious，but many of us cut down an hour or two off our sleep time in the morning or at night to do other things. Most adults need seven to nine hours a night，and teenagers usually need a full nine hours. Block out eight or nine hours for sleep every night.
2．Keep distractions out of bed.
“Remember your bed is only for sleep，” says the scientist.“You shouldn’t read，watch TV，play video games，or use laptop computers in bed.” Don’t do your bills or have heated discussions in bed，either. They may leave you sleepless.
3．Form a good habit.
You should form a good habit of going to bed and getting up at the same time at night and in the morning，including on weekends.
4．Gradually move to an earlier bedtime.
Another way of getting into a consistent (始终如一的) schedule is to try going to bed 15 minutes earlier each night for four nights. Then stick with the last bedtime. Slowly getting used to your schedule like this usually works better than suddenly trying to go to sleep an hour earlier.
5．Set consistent，healthy mealtimes.
Regular mealtimes，not just regular sleep times，help regulate our circadian rhythms (生理节奏)．Eat a healthy breakfast and lunch on time instead of grabbing a piece of cake and coffee in the morning or a late sandwich on the run. Try to finish eating meals two or three hours before bedtime.
6．Exercise.
Regular exercise offers many benefits for sleep. Exercise generally makes it easier to fall asleep and sleep more soundly.
The writer wrote this passage to ________.

A．explain why sleeping well is important

B．tell us what usually keeps us awake at night

C．tell us the harm of being sleepy in the daytime

D．give us some tips on how to avoid daytime sleepiness

What does the underlined word “adequate” in Point 1 mean?

A．Enough.

B．Special.

C．Better.

D．Long.

According to the writer，if we want to change our habits and go to sleep an hour earlier，we should ________.

A．try going to sleep an hour earlier suddenly

B．try getting used to our new schedule slowly

C．try getting used to our new schedule with some help

D．try going to bed 10 minutes earlier each night for six nights

From Point 5 we know if we want to sleep around 10 pm，we should have supper at least by ________.

A．6∶00 p．m.

B．7∶00 p．m.

C．8∶00 p．m.

D．9∶00 p．m.