NB. This article refers to British English.
END THE CONFUSION (1): FORGET or LEAVE?
Here’s the situation: You get to your English class and you realise you have forgotten to bring your notebook. Yikes!
You can either tell your teacher,
“Sorry, I’ve forgotten my notebook,”
“Sorry, I’ve left my notebook at home.”
However, you CAN’T say, “Sorry, I’ve forgotten my notebook at home.”
When you mention the place where the object is now, do not use ‘forget’, despite the fact that the reason why it is there is that you forgot it!
Forget + object
Leave + object + place where it is now
He has forgotten his wallet.
He has left his wallet in the car.
I can’t find my phone. I must have forgotten to bring it.
I can’t find my phone. I hope I didn’t leave it in the restaurant/at the office.
On a further note, of course you could leave something (or somebody) in a place on purpose, but usually the context will tell us whether the action was deliberate or not.
I left my laptop at home because my sister wanted to borrow it. (deliberate)
The children weren’t interested in coming so we left them at home with granny. (deliberate)
Oh no! I’ve left my passport on the plane. I’m going to go back and get it. (I forgot it)
She was in such a rush that she left her presentation at home. (She forgot it)