Please choose the correct ending to complete the given sentence: Computers and Electronics: [header] How to fall asleep fast [title] Keep your room dark. [step] Keep lights dim an hour before bedtime, and turn off all overhead lights, night lights, and lamps when you go to bed. Any bright light (not just electronic devices' screens) can trick your body into thinking it's too early in the day for sleep.

Ending1: The new time you set for sleep makes it harder for your body to process the day's events. Let your body do the work, and go to sleep with the lights off. Ending2: Avoid getting into bed at any time before your alarm. [substeps] When sleeping, remove all electronics from your room at least 20 minutes before bedtime and wear a simple sleeping mask or blackout blanket. Ending3: [substeps] If you want to read or write before bed, try using a small book light rather than a desktop lamp or overhead light. Bluish light can keep you awake, so go for a bulb that gives off a warm glow. Ending4: [substeps] It's a good idea to invest in good nightlights in your bedroom, so that you can wake up refreshed in the morning. A harder trick to learn during the night than many other methods is making sure your room is cool and dark.

Answer format: ending1/ending2/ending3/ending4