You use this tense when you want to say someone was in the middle of doing something at a specific moment in the past. It is more vivid than the plain imperfect and puts the action in motion, like a snapshot of what was happening right then.
Two pieces. Estar in the imperfect + the gerund (the -ando/-iendo form). Together they mean "was/were doing."
This is the "was/were" part. You already know these forms from the imperfect. Here they are side by side.
Drop the infinitive ending, then add -ando for -ar verbs or -iendo for -er and -ir verbs. This is the "-ing" part.
Drop -ar, add -ando. That's it.
Drop -er or -ir, add -iendo.
Stem-changing verbs that changed in the preterite make the same stem change in the gerund. These are the ones to memorize.
Besides estar, four other verbs can combine with a gerund to describe ongoing action. These verbs are conjugated directly, with no estar needed. They each add a slightly different shade of meaning.
Tap any card to check your answer.
Give the gerund (-ando/-iendo form) of each verb. Tap to check.
Say the full sentence using estar imperfect + gerund. Tap to check.
Write the correct form of estar in the imperfect AND the gerund. Then check your answers.