(modal; past form of can)
бы(используется для вежливых просьб) Could you pass me the paper?
Вы не могли бы передать мне эту бумагу?
возможно(используется для предположений) You could be right, but we need to doublecheck everything.
Возможно, Вы и правы, но надо всё проверить.
Synonyms
were able to
had the capacity to
would be able to
managed to
had the ability to
was capable of
might be able to
was able to