Expressing "Should Have"
To talk about things that should have happened but didn't, Romanian uses the perfect conditional of a trebui (to have to) followed by să and the present subjunctive of the main action verb.
Because a trebui is impersonal in this specific usage, it stays fixed as ar fi trebuit regardless of who the subject is. The verb following să, however, changes to match who "should have" done the action. Let's look at some examples involving unidentified flying objects (OZN-ul).
| We should have seen the UFO on our radar. | Ar fi trebuit să vedem OZN-ul pe radarul nostru. |
| The flying saucer should have landed here. | Farfuria zburătoare ar fi trebuit să aterizeze aici. |
Expressing "Could Have"
To express what someone "could have" done (unfulfilled past ability), use the perfect conditional of a putea (to be able to) followed by să and the present subjunctive.
Unlike a trebui, a putea changes its helper verb depending on who is doing the action. For the third person (he/she/it/they), it takes the form ar fi putut.
| The military man could have caught the alien yesterday. | Militarul ar fi putut să prindă extraterestrul ieri. |
| Their ship could have destroyed the whole galaxy. | Nava lor ar fi putut să distrugă toată galaxia. |
Negation and Complex Scenarios
Making these past modals negative is simple: place nu directly before the conditional helper verb, resulting in nu ar fi trebuit (shouldn't have) or nu ar fi putut (couldn't have).
These structures are perfect for discussing prevented disasters, mistakes, or things that went wrong—such as extraterrestrial abductions (a răpi) or an impending invasion (invazia).
| The alien shouldn't have abducted anyone. | Extraterestrul nu ar fi trebuit să răpească pe nimeni. |
| The invasion could have been more and more dangerous. | Invazia ar fi putut să fie din ce în ce mai periculoasă. |
| We should have returned to the military base, but the radar broke down. | Ar fi trebuit să ne întoarcem la baza militară, dar radarul s-a stricat. |
