I
can speak Spanish, but I
can't speak Japanese.
You can't park your car here; it's a no-parking zone.
After months of practice, she is able to play the song perfectly.
He wasn't able to finish the report on time because his computer crashed.
My grandfather could run very fast when he was young.
We could leave early if we finished our work.
I couldn't swim until I was ten years old.
She could have helped us yesterday, but she wasn't able to get time off work.