CONDITIONALS
There are three types of more complex conditionals in Latin, all of which take the subjunctive and all of which relate to less concrete (or more abstract) situations. I recommend that you approach these like formulas to be learnt, and then aim to plug in the correct formula when needed in a text. Here they are, with their easier and more technical names (I tend just to use the former).
(i) A were-would clause (or "contrary-to-fact present"): imperfect subjunctive in both halves.
si veniret, laetum essem, "If he were to come, I would be happy." These are for something that’s possible, but not immediately probable.
(ii) A had-would have clause (or "contrary-to-fact past"): pluperfect subjunctive in both halves.
si venisset, laetus fuissem. "If he had come, I would have been happy." These are distinguished by the fact that they are no longer possible; you can always add a but to the first half. "If he had come (but he didn’t), I would have been happy."
(iii) A should-would clause (or "future less vivid"): present subjunctive in both halves.
si veniat, laetus sim. ‘If he should come, I would be happy’. The circumstance imagined in a should-would clause is possible, and more probable than in type (i).
There are three types of more complex conditionals in Latin, all of which take the subjunctive and all of which relate to less concrete (or more abstract) situations. I recommend that you approach these like formulas to be learnt, and then aim to plug in the correct formula when needed in a text. Here they are, with their easier and more technical names (I tend just to use the former).
(i) A were-would clause (or "contrary-to-fact present"): imperfect subjunctive in both halves.
si veniret, laetum essem, "If he were to come, I would be happy." These are for something that’s possible, but not immediately probable.
(ii) A had-would have clause (or "contrary-to-fact past"): pluperfect subjunctive in both halves.
si venisset, laetus fuissem. "If he had come, I would have been happy." These are distinguished by the fact that they are no longer possible; you can always add a but to the first half. "If he had come (but he didn’t), I would have been happy."
(iii) A should-would clause (or "future less vivid"): present subjunctive in both halves.
si veniat, laetus sim. ‘If he should come, I would be happy’. The circumstance imagined in a should-would clause is possible, and more probable than in type (i).