In the previous lesson, we learned how to form the conditionnel passé (past conditional) to imagine alternate realities. Another major use of this tense is to express regrets about your own past actions, or to reproach someone else for their poor decisions.
"Should have" with Devoir
To express that someone "should have" done something, use the past conditional of the verb devoir.
The formula is: avoir (in the conditional) + dû + infinitive verb.
Use this to express personal regrets about missed opportunities or bad choices—like holding onto a risky stock for too long.
| The broker should have sold the stock. | Le courtier aurait dû vendre l'action. |
| The stock collapsed, I should have listened to your advice. | L'action s'est effondrée, j'aurais dû écouter ton conseil. |
Expressing Reproaches
When you use this same structure with tu or vous, it becomes a reproach—a way of criticizing someone else's past decision or lack of action.
| You knew it, you should have warned me before the crash. | Tu le savais, tu aurais dû m'avertir avant le krach. |
"Should not have"
To say what someone "should not have" done, simply place ne (or n') and pas (or another negative word like jamais) around the auxiliary verb.
The negation goes before the word dû.
| It was too risky, I should not have invested. | C'était trop risqué, je n'aurais pas dû investir. |
| He should never have bet all his capital. | Il n'aurait jamais dû miser tout son capital. |
"Could have" with Pouvoir
Similarly, you can use the past conditional of the verb pouvoir to talk about a missed ability or opportunity—what someone "could have" done to prevent a disaster.
The formula is: avoir (in the conditional) + pu + infinitive verb.
| They could have avoided the crash, but they preferred to speculate. | Elles auraient pu éviter le krach, mais elles ont préféré spéculer. |
Putting it all together
You will often see reproaches and regrets combined in the same thought. You can use aurait dû to call out the mistake, and a regular past conditional verb to describe the disaster you would have avoided.
| You should have warned me before betting everything, we would have avoided this loss. | Tu aurais dû m'avertir avant de tout miser, nous aurions évité cette perte. |
