sleep

sleep, asleep 

You usually use be asleep rather than 'be sleeping' 

Her parents were already asleep (NOT already slept/were sleeping). 

The verb sleep is used when you are giving more

 information,

for example about how long someone sleeps or where they sleep •

The baby sleeps for 12 hours. •

He slept in the car. You usually say fall asleep, not 'start sleeping' •

Some students fall asleep (NOT start sleeping/start to sleep) at their desks

 Do not say 'feel asleep'.

You can also say someone goes to sleep, especially when they are in bed and want to sleep •

I turned the light out and went to sleep.

 You use get to sleep when someone has difficulty falling asleep •

 It took me hours to get to sleep.