Not all sleep is thesame every night.We experience some deep,quiet sleep and some activesleep,which is when dreams happen.You might think sleepwalking would happen

during activesleep,but a person isn't physically active during active sleep.Sleepwalkingusually happens in the first few hours of sleep in the stage called slow-waveor deep

sleep.

Not all sleepwalkersactually walk.Some simply sit up or stand in bed or act like they're awake whenin fact,they're asleep! Most,however,do get up and move around for a

few seconds or foras long as haff an hour.

Sleepwalkers' eyesare open,but they don't see the same way they do when they're awake and oftenthink they're in different rooms of the house or different places altogether.

Sleepwalkers tend togo back to bed on their own and they won't remember it in the morning.

Researchers estimatethat about 15% of kids sleepwalk regularly. Sleepwalking may run in families（在家族中世代相传）and sometimes occurs when aperson is sick, has

a fever, is notgetting enough sleep,or is stressed（紧张）.

If sleepwalkingoccurs frequently,every night or so,it's a good idea for your mom or dad totake you to see your doctor. But occasional sleepwalking generally isn'tsomething

to worry about,althoughit may look funny or even scary（骇人的）for the people who see a sleepwalker in action.

Although occasionalsleepwalking isn't a big deal,it's important,of course,that the person is keptsafe. Precautions（预防措施）shouldbe taken so the person is less likely to

fall down, run intosomething,or walk out the front door while sleepwalking.Sleepwalkersusually go back to bed__________.

A.after waking up

B.after being wokenup

C.with the help ofothers

D.by themselves