altérer — French conjugation
to alter; change; fiddle with
Indicative
Present (Présent) Irregular
Use the présent for habits, what is true now, and what is about to happen soon. A single set of endings covers what English often splits into “I speak” and “I am speaking”.
Elle parle arabe et français.
| Pronoun | French | English |
|---|---|---|
| je | altère | I alter |
| tu | altères | you alter |
| il/elle | altère | he/she/it alters |
| nous | altérons | we alter |
| vous | altérez | you (pl.) alter |
| ils/elles | altèrent | they alter |
Simple past (Passé simple) Regular
The passé simple narrates completed past events in a literary or very formal style. In everyday conversation people use the passé composé instead, so you mostly meet this form in books and journalism.
Ils virent le roi s'approcher.
| Pronoun | French | English |
|---|---|---|
| je | altérai | I altered |
| tu | altéras | you altered |
| il/elle | altéra | he/she/it altered |
| nous | altérâmes | we altered |
| vous | altérâtes | you (pl.) altered |
| ils/elles | altérèrent | they altered |
Imperfect (Imparfait) Regular
The imparfait describes ongoing or repeated past actions and sets the background — how things were, what used to happen, weather, feelings. The passé composé, by contrast, marks single completed events.
Quand j'étais petit, j'allais souvent à la piscine.
| Pronoun | French |
|---|---|
| je | altérais |
| tu | altérais |
| il/elle | altérait |
| nous | altérions |
| vous | altériez |
| ils/elles | altéraient |
Conditional (Conditionnel) Regular
The conditionnel is for polite questions and requests, “would”-type hypotheticals, and what someone said would happen. It is also the usual consequent clause in si + imparfait → conditionnel patterns.
Pourriez-vous répéter, s'il vous plaît ?
| Pronoun | French | English |
|---|---|---|
| je | altérerais | I would alter |
| tu | altérerais | you would alter |
| il/elle | altérerait | he/she/it would alter |
| nous | altérerions | we would alter |
| vous | altéreriez | you (pl.) would alter |
| ils/elles | altéreraient | they would alter |
Future (Futur) Regular
The futur is for future plans and objective predictions. In speech, aller + infinitive is often clearer for the immediate future, while the simple future is common for facts further ahead or in writing.
Demain, nous dînerons chez eux.
| Pronoun | French | English |
|---|---|---|
| je | altérerai | I will alter |
| tu | altéreras | you will alter |
| il/elle | altérera | he/she/it will alter |
| nous | altérerons | we will alter |
| vous | altérerez | you (pl.) will alter |
| ils/elles | altéreront | they will alter |
Present perfect (Passé composé) Regular
The passé composé is the main spoken past for completed, bounded actions (often with a time adverb). Use avoir with most verbs; être is required for a fixed group of motion/inchange and all pronominal verbs, with participle agreement when necessary.
Elle est venue tôt, puis elle a téléphoné.
| Pronoun | French | English |
|---|---|---|
| je | j'ai altéré | I have altered |
| tu | tu as altéré | you have altered |
| il/elle | il/elle a altéré | he/she/it has altered |
| nous | nous avons altéré | we have altered |
| vous | vous avez altéré | you (pl.) have altered |
| ils/elles | ils/elles ont altéré | they have altered |
Pluperfect (Plus-que-parfait) Regular
The plus-que-parfait is the “earlier past”: one action was already over before another past moment. It answers “had already” when a story is anchored in a past time.
Déjà, il avait fini quand je suis arrivé.
| Pronoun | French | English |
|---|---|---|
| je | j'avais altéré | I had altered |
| tu | tu avais altéré | you had altered |
| il/elle | il/elle avait altéré | he/she/it had altered |
| nous | nous avions altéré | we had altered |
| vous | vous aviez altéré | you (pl.) had altered |
| ils/elles | ils/elles avaient altéré | they had altered |
Conditional perfect (Conditionnel passé) Regular
The conditionnel passé states what would have been true, plans that failed, and unreal past if-clauses (often with si + plus-que-parfait in the apodose).
J'aurais dit oui, mais c'était impossible.
| Pronoun | French |
|---|---|
| je | j'aurais altéré |
| tu | tu aurais altéré |
| il/elle | il/elle aurait altéré |
| nous | nous aurions altéré |
| vous | vous auriez altéré |
| ils/elles | ils/elles auraient altéré |
Future perfect (Futur antérieur) Regular
The futur antérieur marks an action that will be finished before a later future moment (by then I will have…). It can also suggest a conjecture about a recent past fact in formal or literary use.
D'ici samedi, j'aurai lu le rapport.
| Pronoun | French | English |
|---|---|---|
| je | j'aurai altéré | I will have altered |
| tu | tu auras altéré | you will have altered |
| il/elle | il/elle aura altéré | he/she/it will have altered |
| nous | nous aurons altéré | we will have altered |
| vous | vous aurez altéré | you (pl.) will have altered |
| ils/elles | ils/elles auront altéré | they will have altered |
Subjunctive
Present subjunctive (Subjonctif présent) Irregular
The present subjunctive appears in subordinate clauses after desire, doubt, fear, need, and many impersonals, usually when the subject of the subordinate is different. Learn common triggers: il faut que, je veux que, je doute que…
Il faut qu'il parte avant midi.
| Pronoun | French |
|---|---|
| je | altère |
| tu | altères |
| il/elle | altère |
| nous | altérions |
| vous | altériez |
| ils/elles | altèrent |
Imperfect subjunctive (Subjonctif imparfait) Regular
The imparfait du subjonctif is a literary and formal past subjunctive. In modern speech, the present subjunctive usually replaces it for the same meaning.
Bien qu'il fût fatigué, il continua.
| Pronoun | French |
|---|---|
| je | altérasse |
| tu | altérasses |
| il/elle | altérât |
| nous | altérassions |
| vous | altérassiez |
| ils/elles | altérassent |
Other forms
Imperative (Impératif) Regular
The imperative is for direct orders and advice to tu, nous, and vous. For many -er verbs, the tu form drops the final -s of the present (parle!); negatives use the subjunctive-like forms in practice.
Fermons la porte, s'il vous plaît !
| Pronoun | French |
|---|---|
| tu | altère |
| nous | altérons |
| vous | altérez |