Modal Verbs: Present Perfect Forms

Present Perfect Forms of Modals

• Probability and Degrees of Certainty in the Past -> Modals + Have + Past Participle
• Don't know/ Uncertain -> Might (not)/ May (not)/ Could
• Almost Certain/ Highly Probable or Improbable -> Must (not)/ Can't/ Couldn't/ Should (not)
• 100% Cartain -> Simple Past
• Examples:
• "He might have stayed up all night."
• "She may not have seen him leave."
• "He must have been up late."
• "She can't have forgotten his trip."
• "He stayed up all night."
• Past Unreal Conditionals (contrary to reality) -> Would/ Could + Have + Past Participle
• Example:
• "He would have gone to bed early, but he had to prepare for a business trip."
• "Yvone could have halped him prepare, but she feel a sleep."
• Regrets (or when what happened was the opposite of what was desirable) -> Should (not) + Have + Past Participle
• Example:
• "He shouldn't have stayed up so late."
• "His boss should have told him sooner."