I won't be able to (do something)

"Not able to" means "can't". So "I won't be able to" means that you can't do something in the future.

You use this expression when you are saying "no" to an invitation or changing a plan that you made:

I won't be able to stay for very long.

I'm really sorry, but I won't be able to attend.

This phrase appears in these lessons: