A subordinate clause is a clause that works inside a larger sentence. In the finite patterns mapped here, it has a conjugated verb but depends on another element: a predicate may select it, an event may be placed in time or given a cause, or a noun may be identified by it. Greek complex sentences become much easier once you sort these subordinate clauses into three families: complement, adverbial, and relative.
The three attachment patterns
| Clause type | Attaches to | Typical markers | Job |
|---|---|---|---|
| Complement | a verb, adjective, or impersonal predicate | ότι, πως, να, αν | fills a selected content slot: what is known, wanted, or questioned |
| Adverbial | the event of the main clause | όταν, επειδή, για να, αν | adds time, cause, purpose, condition, and similar relations |
| Relative | a noun phrase | που, ο οποίος | identifies or describes a person, thing, time, or place |
The most reliable diagnostic is therefore not the English translation of the linker. Ask what the clause is attached to. A complement completes a predicate, an adverbial modifies an event, and a relative modifies a noun.
Complement clauses fill a content slot
Some predicates are incomplete until their content is supplied. Ξέρω invites “what do you know?”, θέλω invites “what do you want to happen?”, and αναρωτιέμαι invites “what are you wondering?” The dependent clause answers that question.
Ξέρω ότι το κατάστημα κλείνει στις οκτώ.
kséro óti to katástima klíni stis októ
I know that the shop closes at eight.
Θέλω να μιλήσουμε πριν πάρουμε απόφαση.
thélo na milísume prin párume apófasi
I want us to talk before we make a decision.
Δεν ξέρω αν έχει μείνει κανείς στο γραφείο.
dhen kséro an échi míni kanís sto ghrafío
I don't know whether anyone is still at the office.
In the first example the ότι-clause is the information known. In the second the να-clause is the desired event. In the third the αν-clause is an unresolved yes/no question. These are object-like functions even though the complement is a whole clause.
A complement can also occupy a subject-like position, particularly with an impersonal evaluation:
Είναι σημαντικό να κρατήσεις όλα τα μηνύματα.
íne simandikó na kratísis óla ta minímata
It is important to keep all the messages.
Greek uses a finite να-clause where English often uses an infinitive. The person remains visible on the Greek verb: να κρατήσω, να κρατήσεις, να κρατήσουμε. The detailed selection system is mapped on complement clauses.
Adverbial clauses organize events
An adverbial clause does not name an argument of the main verb. It locates the main event in a wider relation: when it happens, why it happens, what goal it serves, or under what condition it becomes possible.
Όταν τελειώσει η σύσκεψη, θα σου στείλω μήνυμα.
ótan teliósi i sískepsi, tha su stílo mínima
When the meeting ends, I'll send you a message.
Μείναμε μέσα επειδή φυσούσε πολύ.
míname mésa epidhí fisúse polí
We stayed inside because it was very windy.
Έβαλα υπενθύμιση για να μην ξεχάσω το ραντεβού.
évala ipenthímisi ya na min ksecháso to randevú
I set a reminder so that I wouldn't forget the appointment.
Αν βρεις εισιτήρια, πάρε και για μένα.
an vris isitíria, páre ke ya ména
If you find tickets, get one for me too.
Many adverbial clauses can precede or follow the main clause. Initial position establishes a frame; final position commonly adds the explanation or goal afterward. Their order, punctuation, and stacking are the subject of adverbial clauses.
Relative clauses modify a noun
A relative clause attaches to a head noun. It either identifies which referent is meant or adds extra information about a referent already identified.
Η κοπέλα που μας βοήθησε δουλεύει στο διπλανό φαρμακείο.
i kopéla pu mas voíthise dhulévi sto dhiplanó farmakío
The woman who helped us works at the pharmacy next door.
Ο κύριος Παπαδόπουλος, ο οποίος διευθύνει το τμήμα, θα υπογράψει την επιστολή.
o kírios Papadhópulos, o opíos dhiefthíni to tmíma, tha ipoghrápsi tin epistolí
Mr Papadopoulos, who heads the department, will sign the letter. (formal)
The everyday invariable relative is που. Declined ο οποίος is heavier and especially useful in formal writing (formal). The comma in the second example says that the clause adds information rather than selecting one Mr Papadopoulos from several. The syntax of attachment and punctuation is consolidated on relative clauses.
Mood follows viewpoint, not clause size
Subordination does not automatically trigger one mood. Clauses presented as facts normally contain indicative forms: ξέρω ότι έκλεισε, επειδή έβρεχε, αν και ήταν αργά. Clauses presenting wishes, goals, requirements, or other envisaged events often use να: θέλω να φύγω, για να προλάβω.
Future time clauses add an important refinement. A linker such as όταν can directly license a perfective dependent form without overt να:
Όταν φτάσεις στον σταθμό, τηλεφώνησέ μου.
ótan ftásis ston stathmó, tilefónisé mu
When you reach the station, call me.
Here φτάσεις is not a present factual assertion; it presents one awaited completion. The detailed aspect choices belong to the clause-type pages. At A2, keep the central tendency illustrated here: factual or habitual clauses commonly use indicative forms, while να and bare dependent forms commonly present actions as envisaged, awaited, or goal-directed.
Clauses can nest
A complex sentence can contain more than one subordinate type, and each keeps its own attachment.
Ξέρω ότι το λεωφορείο που περιμένουμε θα φύγει όταν γεμίσει.
kséro óti to leoforío pu periménume tha fíyi ótan yemísi
I know that the bus we're waiting for will leave when it fills up.
The outer ότι-clause completes ξέρω. Inside it, που περιμένουμε modifies το λεωφορείο, while όταν γεμίσει gives the time for θα φύγει. Reading from the attachment outward prevents the sentence from becoming a flat chain of conjunctions.
Common Mistakes
1. Using a factual complementizer for an embedded yes/no question.
❌ Αναρωτιέμαι ότι θα ανοίξει το μουσείο τη Δευτέρα.
Incorrect—an unresolved yes/no question after αναρωτιέμαι requires αν.
✅ Αναρωτιέμαι αν θα ανοίξει το μουσείο τη Δευτέρα.
anarotiéme an tha aníksi to musío ti Dheftéra
I wonder whether the museum will open on Monday.
2. Using bare οποίο as if it were English “which.”
❌ Το μήνυμα οποίο έστειλες δεν έχει φτάσει ακόμα.
Incorrect—the declined relative requires its article, το οποίο; everyday που also works.
✅ Το μήνυμα που έστειλες δεν έχει φτάσει ακόμα.
to mínima pu éstiles dhen échi ftási akóma
The message you sent hasn't arrived yet.
3. Building a purpose clause with factual ότι.
❌ Πήγα νωρίς για ότι βρω θέση μπροστά.
Incorrect—an intended goal uses the unit για να.
✅ Πήγα νωρίς για να βρω θέση μπροστά.
pígha norís ya na vro thési brostá
I went early to find a seat at the front.
Key Takeaways
- Complement clauses fill a content slot, adverbial clauses relate events, and relative clauses modify nouns.
- The clause marker is a clue, but attachment is the decisive test.
- Indicative forms tend to present facts; να and dependent forms tend to present wishes, goals, possibilities, and awaited events.
- Several clause types can nest inside one sentence without losing their separate functions.
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Start learning Greek →Related Topics
- Relative ClausesB1 — Understand how Greek relative clauses attach to a head noun, how commas change their scope, how far they may move, and which verb controls agreement.
- Adverbial ClausesB1 — Organize Greek adverbial clauses by order, punctuation, mood, and viewpoint, then combine time, cause, purpose, concession, and condition in one sentence.
- Complement Clauses: ότι / πως / που / ναB1 — See which Greek verb classes select ότι/πως, που, or να, and how one matrix verb changes meaning when its complementizer changes.