The Three Types of Subordinate Clause

A subordinate clause is any clause that cannot stand alone — it leans on a main clause and fills a grammatical role inside it. Dutch has exactly three kinds, sorted by what job they do: complement clauses that act as arguments (subject or object), adverbial clauses that modify the main clause like an adverb, and relative clauses that modify a noun. The payoff of learning them together is that they all obey one and the same word-order law: the finite verb travels to the end of the clause. Once you see that the three types share this single rule, the verb-final order stops feeling like three rules to memorise and becomes one principle with three applications.

The shared rule: verb-final

In a main clause the finite verb sits in second position (the V2 rule). The instant a clause becomes subordinate, that verb deserts second position and goes to the very end, joining any other verbs in a cluster there (see Verb-Final Order in Subordinate Clauses). This holds for all three types without exception. Whatever introduces the clause — a conjunction, a relative pronoun, a question word — flips the same switch.

Type 1: complement clauses (dat / of)

A complement clause functions as an argument of the main verb — it fills the slot a subject or an object would otherwise occupy. It is introduced by dat (that) for statements or of (whether/if) for embedded yes/no questions. You can usually test for a complement clause by replacing it with dat / het (that / it): if Ik weet dat hij komt answers "what do you know?", the dat-clause is the object.

Two things to note. First, English often drops the conjunction that — "I know he's coming" — but Dutch cannot drop dat; it must be present. Second, of means whether/if only in embedded questions; do not confuse it with the conditional als (if). Ik weet niet *of hij komt (I don't know *whether he's coming), but Ik kom *als hij komt (I'll come *if he comes).

Type 2: adverbial clauses (omdat, als, terwijl, toen...)

An adverbial clause modifies the whole main clause the way an adverb would — it tells you why, when, under what condition, despite what. It is introduced by a subordinating conjunction such as omdat (because), als (if/when), terwijl (while), toen (when, past), hoewel (although), zodat (so that), voordat (before), nadat (after). Unlike a complement clause, it is not an argument — the main clause is grammatically complete without it; the adverbial clause simply adds circumstance.

When an adverbial clause comes first, the entire clause counts as a single constituent filling the first position of the main clause — so the main clause's finite verb must come second, before its subject. This is the famous "comma, verb" pattern: Toen we aankwamen, *was het feest...*. English keeps subject before verb here ("When we arrived, the party had..."), which is why this inversion is one of the most persistent errors English speakers make.

Type 3: relative clauses (die / dat / waar-)

A relative clause modifies a noun, telling you which one or giving extra information about it. It is introduced by a relative pronoun — die (persons, de-words, plurals), dat (het-words), or a waar-form for prepositional relations (see Relative Clauses). The relative clause sits right after the noun it describes and, like the others, sends its verb to the end.

Relative dat versus complement dat

The single sharpest confusion between the types is the two uses of dat. They look identical but do different jobs:

• Complement dat is a conjunction meaning that; it introduces an argument clause and refers to nothing. Ik weet *dat het waar is. (I know *that it's true.)
• Relative dat is a pronoun meaning which/that; it stands in for a het-word noun and refers back to it. Het boek *dat ik lees... (The book *which I'm reading...)

The test: can you replace it with which? If yes, it is the relative pronoun and refers to a noun. If it means that = the fact that, it is the complement conjunction. The example above stacks both in one sentence — a clean illustration that they are genuinely different words wearing the same coat.

Common Mistakes

Key Takeaways

• Dutch has three subordinate clause types: complement (argument), adverbial (modifier), relative (noun-modifier).
• All three are verb-final — the finite verb goes to the very end; this is the unifying rule.
• A fronted subordinate clause is one constituent, so the main clause inverts: "comma, verb, subject."
• dat cannot be dropped (unlike English that); of = whether in embedded questions, distinct from conditional als.
• Relative dat (a pronoun, replaceable by which) is a different word from complement dat (a conjunction).