Permission, obligation, and necessityThe full modal and semi-modal range, including past forms.Related learning areasEnglish GrammarRelated conceptsAdding emphasis — cleft sentencesAdding emphasis — inversionAdvanced gerunds and infinitivesConditional sentences — full rangeDiscourse markers — adverbs and adverbial expressionsDiscourse markers — linkersQuestionsAll questions in this subjectStart learningStart free practice