The imparfait tense in French is all about describing ongoing or habitual actions in the past. It's like painting a picture of what was happening or what used to happen regularly.

To form the imparfait, you need to know the verb stems and endings. For regular verbs, it's pretty straightforward. But watch out for those tricky irregular verbs - they like to keep us on our toes!

Stems of regular and irregular verbs

Regular verb stems

The stem of a regular -er verb is formed by removing the -er ending from the infinitive (parler becomes parl-)
The stem of a regular -ir verb is formed by removing the -ir ending from the infinitive and adding -iss (finir becomes finiss-)
The stem of a regular -re verb is formed by removing the -re ending from the infinitive (vendre becomes vend-)

Irregular verb stems

Irregular verbs (être, avoir, faire, aller) have unique stems in the imparfait tense that must be memorized
- être has the stem ét-
- avoir has the stem av-
- faire has the stem fais-
- aller has the stem all-
Some irregular verbs follow patterns based on their infinitive ending
- Verbs ending in -aire (faire, plaire) have the stem fais- in the imparfait
- Verbs ending in -oire (croire, boire) have the stems croy- and buv- respectively in the imparfait
- Verbs ending in -ure (lire, écrire) have the stems lis- and écriv- respectively in the imparfait

Imparfait endings for verbs

The imparfait endings are the same for all verbs, regardless of their infinitive ending or regularity: -ais, -ais, -ait, -ions, -iez, -aient
These endings are added to the stem of the verb to form the imparfait tense conjugation (parler becomes parlais, parlais, parlait, parlions, parliez, parlaient)
The nous and vous forms of the imparfait tense have the same pronunciation as their present tense counterparts, but the spellings differ
- nous parlons (present) vs. nous parlions (imparfait)
- vous parlez (present) vs. vous parliez (imparfait)

Conjugating verbs in the imparfait

Regular verb conjugation

To conjugate a regular verb, first identify the stem by removing the infinitive ending (-er, -ir, -re), then add the appropriate imparfait endings
Common regular verbs conjugated in the imparfait:
- parler: parlais, parlais, parlait, parlions, parliez, parlaient
- finir: finissais, finissais, finissait, finissions, finissiez, finissaient
- vendre: vendais, vendais, vendait, vendions, vendiez, vendaient

Irregular verb conjugation

Irregular verbs have unique stems in the imparfait that must be memorized before adding the imparfait endings
Common irregular verbs conjugated in the imparfait:
- être: étais, étais, était, étions, étiez, étaient
- avoir: avais, avais, avait, avions, aviez, avaient
- faire: faisais, faisais, faisait, faisions, faisiez, faisaient
- aller: allais, allais, allait, allions, alliez, allaient

Irregular verb patterns in the imparfait

Verbs ending in -aire, -oire, -ure

Verbs ending in -aire (faire, plaire) use the stem fais- in the imparfait
- faire: faisais, faisais, faisait, faisions, faisiez, faisaient
- plaire: plaisais, plaisais, plaisait, plaisions, plaisiez, plaisaient
Verbs ending in -oire (croire, boire) use the stems croy- and buv- respectively in the imparfait
- croire: croyais, croyais, croyait, croyions, croyiez, croyaient
- boire: buvais, buvais, buvait, buvions, buviez, buvaient
Verbs ending in -ure (lire, écrire) use the stems lis- and écriv- respectively in the imparfait
- lire: lisais, lisais, lisait, lisions, lisiez, lisaient
- écrire: écrivais, écrivais, écrivait, écrivions, écriviez, écrivaient

Verbs with irregular present tense nous forms

Verbs with irregular present tense nous forms (boire - nous buvons, prendre - nous prenons) use the irregular nous form minus the -ons ending as the stem in the imparfait
- boire: buvais, buvais, buvait, buvions, buviez, buvaient
- prendre: prenais, prenais, prenait, prenions, preniez, prenaient

Unique irregular verbs

Some irregular verbs (être, avoir, faire, aller) have completely unique stems in the imparfait that do not follow any specific pattern and must be memorized individually
- être: étais, étais, était, étions, étiez, étaient
- avoir: avais, avais, avait, avions, aviez, avaient
- faire: faisais, faisais, faisait, faisions, faisiez, faisaient
- aller: allais, allais, allait, allions, alliez, allaient