Past modals for judgments and suggestions
When we judge past actions we use: should (n´t) have
should (n´t) have We use should (n´t) have when we give an opinion or judgement about a past situation: Jessica: I didn´t study for the exam. Me: You should´ve studied. It was 50 points. I´m judging Jessica because she didn´t study.
The formula when judging past actions is… subject should have shouldn´t have verb in past participle complement He should have studied more. He (study more) They shouldn´t have drunk that much. They (drink that much) Lucy should have arrived early. Lucy (arrive early) Alex shouldn´t have said that. Alex (say that)
When suggesting alternative past actions we use: could (n´t) have would (n´t) have
would (n´t) have We use would (n´t) have when we are imagining a hypothetical situation happening to us and doing something different: Jessica: I forgave my boyfriend. Me: I wouldn´t have forgiven him. = If I were Jessica, I wouldn’t have forgiven him.
could (n´t) have We use could (nt´t) have when we are suggesting a hypothetical past possibility: Jessica: My boyfriend was sad and I didn´t ask him why. Me: You could have shown more empathy. = You had the chance to show empathy but you didn´t.
The formula for suggesting alternative past actions is… complement subject could (n´t) have would (n´t) have verb in past participle She could have told the truth. She (tell the truth) I wouldn´t have lent him the car. I (lend him the car) Carmen couldn´t have been more discreet. Carmen (be more opportune) I would have finished it at home. I (would finish it at home )