To fall asleep is an expression, a figurative way of saying to go to sleep. However, we don’t say to fall to sleep in English, instead, you can say to go to sleep.
When can we use fell asleep?
If you want to talk about a past event you can say;
- I fell asleep last night/yesterday/last month as fell is the Past Simple of the verb to fall.
When can we use fall asleep?
If you want to refer to right now, your sleep routine or something that you do every night for example, you should use fall asleep as fall in the Present Simple of the verb to fall. For example,
- I always fall asleep after reading a chapter of my book. (this is something that happens every night and is part of your daily routine.)
Here are some more examples of to go to sleep and to fall asleep:
- I went to sleep after midnight last night, I was very tired this morning.
- He goes to sleep at 10 PM every night and wakes up at 7 AM every morning.
- “Did you go to sleep late last night?” asked his mother.
- I always fall asleep while watching the television.
- When he does a late shift at work, it takes him a long time to fall asleep when he gets home.
- The two boys were so tired after the birthday party that they fell asleep on the couch without having their dinner.
- “I fell asleep on the train and missed my stop last night. I had to walk an extra 20 minutes to get home” she complained to her colleague the next day.