Subordinating conjunction - Onderschikkend voegwoord

Click here for self-correcting exercises on subordinating conjunctions.
A subordinating conjunction is used to introduce a subordinate clause.

It is very important that you are aware of subordinating conjunctions, because the sentence structure in a subordinate clause is different from that in a main clause. In a clause following a subordinating conjunction, the finite verb as well as all other verbs occur in the last or penultimate place. The most common subordinating conjunctions are:

als if/when
dat that
hoewel although
of whether
omdat because
nadat after
terwijl while
toen when (in the past)
wanneer when

toen:
Alan en zijn vrienden gingen naar Antwerpen. Ze hadden vakantie.
Alan en zijn vrienden gingen naar Antwerpen toen ze vakantie hadden.
Alan and his friends went to Antwerp when they had their holiday.
omdat
Karins moeder kan niet op Luuk passen. Ze gaat met haar vriendinnen naar de stad.
Karins moeder kan niet op Luuk passen omdat ze met haar vriendinnen naar de stad gaat.
Karin's mother cannot look after Luuk because she's going into town with her friends.

In these examples, the sentence structure in the main clauses differs from that in the subclause. In the subclauses (in both cases here the last clause) the finite verb is in the last position.

Click here to read more about subordinating conjunctions in the Advanced Dutch Grammar.