What is a clause? Main and subordinate clauses

In writing, a sentence can be roughly defined as a stretch of language between a capital letter and a full stop. In spoken language boundaries between sentences tend to be marked by pauses.  These definitions remain imprecise. For grammatical purposes the term clause is often used. A clause can be defined as a stretch of language (written or spoken) containing one finite verb. This means that a clause can be equal to a sentence (as in the above loose definitions), but does not need to be – one sentence can consist of several clauses. In addition to a finite verb, a clause contains a subject, with the exception of imperatives, which never contain a subject. It may also include objects, adjuncts, and non-finite verbs (infinitives and past participles).

In terms of sentence structure there are two types of clauses: main clauses and subordinate clauses (sometimes also called subclauses). The difference lies in the position of the finite verb: in main clauses it occurs in first or second position, in subordinate clauses in penultimate or final position.

Main clauses

In main clauses the finite verb occurs in first or second position, depending on the sentence type. In imperatives and yes/no questions (including either/or-questions) it occurs in first position, in declarative sentences and question-word questions in second position.

Neem de eerste straat rechts. (informal imperative)
Take the first street on your right.

Doet u uw jas uit. (formal imperative)
Take off your coat.

Studeer je in Sheffield? (yes/no question)
Do you study in Sheffield?

Studeer je Nederlands of Spaans? (either/or-question)
Do you study Dutch or Spanish?

Wat studeer je? (question-word question)
What do you study?

Ik studeer Nederlands. (declarative)
I study Dutch.

A main clause is an independent unit. In other words, grammatically a main clause is not dependent on anything else (unlike a subordinate clause, which is dependent on a main clause). However, it is possible to combine two main clauses into a longer sentence by means of a co-ordinating conjunction.

Ik kom uit Colchester in Engeland, maar ik studeer in Hull.
I am from Colchester in England but I study in Hull.

Read more about Sentence structure in main clauses.

Subordinate clauses

Sentence type does not play a role in subordinate clauses: you could argue that they are always declarative. A subordinate clause contains at least subordinating conjunction, a subject and a finite verb. Its finite verb can be found in the last or penultimate position (which is also where any other verbal elements may be found). There are a few exceptions to this, notably certain proportion clauses, conditional clauses without a conjunction and elliptical clauses.

Subclauses are introduced by subordinating conjunctions. If, in other words, you use a subordinating conjunction to link two clauses, the clause following the subordinating conjunction will be the subclause. In the examples below the finite verbs are highlighted, and the subordinating conjunctions are underlined.

Ik ga vaak naar de universiteit, omdat ik bijna elke dag college heb.
I often go to the university because I have lectures nearly every day.

Wanneer ik geen college heb, studeer ik in de bibliotheek.
when I don’t have any lectures, I study in the library.

‘s Maandags ga ik laat naar de universiteit, omdat ik dan pas college heb om zeven uur ‘s avonds.
On Mondays I go to university late, because then I don’t have any lectures until seven o’clock in the evening.

Note that technicaly the whole sentence, including the subordinate clause, is the main clause.

According to Dutch writing conventions, the subordinate clause tends to be separated from the rest of the sentence with a comma. When it takes up the first position of the sentence, the comma is compulsory (as in the second example above between heb and studeer) to separate the two finite verbs clearly.

Unlike a simple main clause, a subordinate clause cannot occur as an independent unit. The following is not a grammatical sentence: *Ik bijna elke dag college heb.

Read more about Sentence structure in subordinate clauses.