Compléter Degrees of certaintyVersion en ligne This exercise can help you practise theory of modals that express certainty, possibility or probability. Your task is to match the missing word in each gap. You start with first gap and then you click on the word that you think is correct. You have 6 minutes to finish this exercise. Good luck! par Karin Tvrdoňová 1 Modal verb express strong certainty but we use it only in meaning . Making deductions about the present things that are true now we use structure + . If we are talking about past events we use different grammar structure that is + + . Modals will , must express something which is nearly , can or could tell you that something is probable or On the other hand if we use may or we express possibility . Don´t forget that modal verb it´s in British English more formal . Both of them do not express but only .