Past modals — must have, might have, should haveDeduction and regret about the past.Related learning areasEnglish GrammarRelated conceptsAdjectives as nouns, and adjective orderArticlesAuxiliary verbs in echoes, agreement, and emphasisClauses of contrast and purposeFuture perfect and future continuousGerunds and infinitivesQuestionsAll questions in this subjectStart learningStart free practice