Learn Dutch: Ik zoek een draad om de lantaarn aan op te hangen. - I am looking for a wire to hang the lantern on.

It might look like two prepositions in a row, but they have different jobs. Aan is the stranded preposition meaning "on" (from the phrase ophangen aan, meaning "to hang up on"). Op is the separable prefix of the verb ophangen. The word te separates the prefix from the verb, giving us the sequence aan op te hangen.

Why isn't there an er combined with aan (like eraan) to mean "on it"?

In an attributive om ... te clause like this, the preposition stands alone. It points directly back to the noun it modifies right before the clause (een draad). Adding er to make eraan would be redundant because the sentence is already saying "a wire to hang the lantern on," not "a wire to hang the lantern on it."

What dictates the word order after om?

The clause starts with om, followed by the object of the action (de lantaarn). Next is the stranded preposition (aan). The phrase always ends with the infinitive verb block. Because ophangen is a separable verb, te splits the prefix from the main verb, giving you op te hangen at the very end.

In English we say "looking for." Why isn't there a translation for "for" after Ik zoek?