3: Modals Last updated Aug 1, 2024 Save as PDF 2.7: Past Perfect vs Past Perfect Progressive 3.1: Modal Verbs Expressing Degrees of Certainty Page ID273141 ( \newcommand{\kernel}{\mathrm{null}\,}\) 3.1: Modal Verbs Expressing Degrees of Certainty3.2: Past Modals of Degrees of Certainty3.3: Could Have and Should Have-Regret and Criticism3.3.1: Should Have3.4: Comparing Could Have and Should Have3.5: Progressive Modals