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Some researchers, parents and teachers have suggested that high-school classes begin later in the morning to accommodate (适应) teens’ needs for more sleep.        However, in the meantime you’ll have to make your own adjustments. Here are some suggestions that may help you to sleep better.
Set a regular bedtime. Going to bed at the same time each night signals to your body that it’s time to sleep.        So try to stick as closely as you can to your sleep schedule, even on weekends.
Exercise regularly.        Finish exercising at least 3 hours before bedtime. Many sleep experts believe that exercising in late afternoon may actually help a person sleep.
Avoid stimulants (刺激物). Don’t drink beverages with caffeine, such as soda and coffee, after 4 pm.        And drinking alcohol in the evening can make a person restless and interrupt sleep.
Relax your mind. Avoid violent, scary or action movies or television shows right before bed. Reading books with active plots may also keep you from falling or staying asleep.
Create the right sleeping environment.      So close your curtains (and make sure they’re heavy enough to block out light) and turn down the thermostat (恒温器). Noise can prevent people from sleeping well. Use a white-noise machine if you need to block out a noisy environment.

A．Waking up at the same time every day also helps establish sleep patterns.

B．People usually sleep best in a dark cool room.

C．Light signals to the brain that it’s time to wake up.

D．Try not to exercise right before bedtime as it can make it harder for you to fall asleep.

E. Nicotine is also a stimulant, so quitting smoking may help you sleep better.
F. Naps too close to bedtime may keep you from falling asleep.
G. Some schools have carried out later start times.