Greek normally gives an eventive verb two past viewpoints, and choosing between them is one of the most frequent aspect decisions you will make. The imperfect is the imperfective past — was doing, used to do — and the aorist is the perfective past — did, viewed as a bounded whole. English and Spanish offer useful analogies, but Greek aspect must still be chosen from the Greek sentence and context.
Two pasts, one verb
Both pasts are built from the same verb but on different stems. The imperfect uses the imperfective stem (γράφ-), the aorist the perfective stem (γράψ-):
| Imperfect (imperfective past) | Aorist (perfective past) | |
|---|---|---|
| Form | έγραφα | έγραψα |
| Stem | γράφ- (imperfective) | γράψ- (perfective) |
| View | internal / ongoing / unbounded | a bounded whole: one event or a finite series |
| English | was writing / used to write | wrote |
How each is actually built — the endings, the augment — is on the imperfect and aorist pages. Here we care only about which one to reach for.
This choice presupposes that the intended meaning supplies both stems. Basic είμαι, έχω, and ξέρω have no same-lexeme aorist for the corresponding state; έγινα, απέκτησα, and έμαθα express changes of state rather than merely changing viewpoint. Do not manufacture a missing partner.
The signature pattern: background cut by an event
The clearest place to feel the difference is a sentence with two past actions: a longer one going on, and a sudden one that breaks in. The ongoing background takes the imperfect; the interrupting event takes the aorist.
Διάβαζα όταν χτύπησε το τηλέφωνο.
dhiávaza ótan chtípise to tiléfono
I was reading when the phone rang. (background: imperfect / event: aorist)
The reading (διάβαζα) is the stretch you were inside of; the ringing (χτύπησε) is presented as a bounded event inside it. Under that intended simultaneous reading, the aorist διάβασα would no longer supply the background: it would package the reading as a whole and invite a different sequence. This template covers an enormous amount of everyday narration:
Περπατούσα στον δρόμο όταν με φώναξε ένας παλιός φίλος.
perpatúsa ston dhrómo ótan me fónakse énas paliós fílos
I was walking down the street when an old friend called out to me.
Ενώ μαγείρευα, κάηκε το φαγητό στον φούρνο.
enó mayíreva, káike to fayitó ston fúrno
While I was cooking, the food burnt in the oven.
Open habit vs bounded occurrence or series
The second big split is one of viewpoint. An open past habit is normally imperfective; one bounded occurrence is normally aorist. Repetition itself does not ban perfective aspect, however: a speaker can package a finite, delimited series as one whole.
Όταν ήμουν φοιτητής, έμενα σε ένα μικρό διαμέρισμα στο κέντρο.
ótan ímun fititís, émena se éna mikró dhiamérizma sto kéndro
When I was a student, I lived in a small flat in the centre. (a standing situation → imperfect)
Πέρσι μετακόμισα σε μεγαλύτερο σπίτι με κήπο.
pérsi metakómisa se meghalítero spíti me kípo
Last year I moved to a bigger house with a garden. (one event → aorist)
Κάθε Κυριακή τρώγαμε όλοι μαζί στης γιαγιάς.
káthe kiriakí tróghame óli mazí stis yayás
Every Sunday we all used to eat together at grandma's. (open habit → imperfect)
Εκείνη την Κυριακή φάγαμε σε μια ταβέρνα δίπλα στη θάλασσα.
ekíni tin kiriakí fághame se mia tavérna dhípla sti thálasa
That particular Sunday we ate at a taverna by the sea. (one occasion → aorist)
Φάγαμε εκεί τρεις φορές εκείνον τον μήνα.
fághame ekí tris forés ekínon ton mína
We ate there three times that month. (finite series packaged as a whole → aorist)
Description and states: the imperfect
When a state or description paints the backdrop of a past scene — the weather, how someone looked, what you knew or felt — no boundary is foregrounded, so the imperfect is natural. Events then presented as bounded against that backdrop are aorist.
Έβρεχε και έκανε κρύο, γι' αυτό μείναμε τελικά μέσα.
évreche ke ékane krío, yaftó míname teliká mésa
It was raining and it was cold, so in the end we stayed in. (backdrop: imperfect / decision: aorist)
Δεν ήξερα ότι είχες γενέθλια, συγγνώμη που δεν σε πήρα!
dhen íksera óti íches yenéthlia, sighnómi pu dhen se píra
I didn't know it was your birthday, sorry I didn't call! (ongoing state of knowledge → imperfect)
The English and Spanish bridges
For an English speaker the rough map is reliable as a starting point:
- was / were + -ing → imperfect (Διάβαζα)
- used to / would (habit) → imperfect (έμενα)
- simple past with a bounded reading → aorist (μετακόμισα)
But the English simple past also covers habits, states and other imperfective readings, while progressive wording can occur around a bounded event. You cannot read Greek aspect straight off the English tense. The Spanish imperfecto/pretérito contrast is a closer analogy, but it is still not a word-for-word transfer rule: lexical aspect, conventional phrasing and the speaker's construal can make Greek and Spanish choose differently.
The honest grey zone
Not every past is a clean call, and pretending so would mislead you. A single durative event — "I worked all day yesterday" — can be told either way, with a real shade of difference. The aorist frames the whole day as one bounded block (δούλεψα όλη μέρα — and that was my day); the imperfect puts you inside the stretch (δούλευα όλη μέρα — the day was one long working). Both are natural Greek. Native speakers themselves vary here, and the full decision procedure — including these judgment calls — lives on the choosing the right aspect guide.
Χθες δούλεψα δώδεκα ώρες και έπεσα ξερός στο κρεβάτι.
chthes dhúlepsa dhódheka óres ke épesa kserós sto kreváti
Yesterday I worked twelve hours and collapsed into bed. (the day as one bounded block → aorist)
Common Mistakes
1. Treating the forms as interchangeable without a change of viewpoint. Both can be grammatical, but they answer different questions.
Όταν με πήρες τηλέφωνο, οδηγούσα προς τη δουλειά.
ótan me píres tiléfono, odhighúsa pros ti dhuliá
When you called me, I was driving to work. (your call falls inside the drive)
Μετά το τηλεφώνημά σου, οδήγησα μέχρι τη δουλειά χωρίς να σταματήσω.
metá to tilefónimá su, odhíyisa méchri ti dhuliá chorís na stamatíso
After your call, I drove all the way to work without stopping. (the drive as a bounded whole)
2. Letting a time word decide by itself. κάθε strongly favours the imperfect for an open habit, but a delimited series can take the aorist.
Κάθε Σάββατο ξυπνούσα αργά.
káthe Sávato ksipnúsa arghá
Every Saturday I used to wake up late. (open habit)
Ξύπνησα αργά και τα τρία Σάββατα των διακοπών.
ksípnisa arghá ke ta tría Sávata ton dhiakopón
I woke up late on all three Saturdays of the holiday. (bounded series)
3. Transferring an English or Spanish form mechanically. Use the other language as a clue, then ask what viewpoint the Greek sentence actually presents.
4. Equating perfective with an objective real-world result. The aorist packages the situation as a whole; the imperfect shows it internally. Context, not the ending by itself, tells you what followed or what still holds now.
Key Takeaways
- Most eventive Greek verbs offer two past viewpoints: the imperfect (imperfective — έγραφα, was writing / used to write) and the aorist (perfective — έγραψα, wrote).
- Use the imperfect for an internal or unbounded view such as background, description and open habit; use the aorist to package an event or finite series as a bounded whole.
- The signature template is a long imperfect frame cut by a sudden aorist: Διάβαζα όταν χτύπησε το τηλέφωνο.
- English and Spanish maps are useful starting points, but neither transfers mechanically; Greek lexical choices and construal can differ.
- Durative single events (worked all day) can go either way with a shade of difference; the choosing guide handles the grey zone.
- The contrast applies only where a verb supplies both stems in the intended meaning; stative or defective verbs may lack a same-lexeme aorist.
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- Using the ImperfectA2 — The four jobs the imperfect (παρατατικός) does — the ongoing background of a past scene, a repeated or habitual past, the description of past states and settings, and a softened, polite request — each set against the bounded viewpoint of the aorist and mapped onto English 'was doing / used to do / would do'.
- Using the AoristA2 — The aorist is Greek's default perfective past: it presents an event, a narrative step, a result or even a finite series as one bounded whole — and often lines up with the English simple past while contrasting with the imperfect's internal view.
- Choosing the Right AspectB1 — The one page to bookmark: for verbs that supply an aspect pair, ask whether the speaker packages an occurrence or finite series as a bounded whole (→ perfective), or views a process, open habit or background from inside (→ imperfective), then work through ten real decisions across the past, future, subjunctive and imperative.