Ability and possibility — can, could, be able toPresent, past, and the forms modals cannot make.Related learning areasEnglish GrammarRelated conceptsArticles — a, an, the, and no articleChoosing between comparatives and superlativesChoosing between conditionalsChoosing between gerunds and infinitivesFirst conditional and future time clausesFuture forms — present continuous, be going to, will and won'tQuestionsAll questions in this subjectStart learningStart free practice