Глакол can заменяем на to be able to… ( связку to be изменяем на am, is, are) Например: Я могу - I am able to…

Он может - He is able to… Мы можем – We are able to…

Глагол could заменяем на was , were able to…

Например: Я мог … I was able to…

Мы могли - We were able to…

В отрицаниях добавляем частицу not: I am not able to…

He is able to go to university next year.
I was able to play football when I was 15.
You are not able to drive a car if you are 6.
Paul was not able to write two years ago.
My mother is able to cook very well.
I am not able to know everything.
My friend was not able to speak when he was ill.
We are able to come only at 4 o’clock.
Nick was not able to buy ice cream as he had no money.
Sara is not able to come to your party.