Learn Dutch: Ik hang de lamp eraan. - I hang the lamp on it.

When talking about things rather than people, Dutch doesn't use a preposition + "it" (you can't say aan het). Instead, it swaps "it" for er (there) and glues the preposition to the end. So er + aan becomes eraan, which literally means "there-on" but translates as "on it" or "to it".

Why use eraan instead of erop if I'm hanging it "on" something?

The Dutch preposition for "on" changes depending on how things connect. Op is for resting on top of a surface (like a book on a table). Aan is used when something is attached, hanging, or touching the side or bottom of something (like a lamp from a ceiling or a picture on a wall). Because the lamp hangs from something, we use eraan instead of erop.

Why is eraan placed at the very end of the sentence?

In standard Dutch word order, the specific object you are acting upon (de lamp) usually comes right after the verb (hang). The "er + preposition" combo (eraan) generally comes after the direct object, pushing it to the end of a short sentence like this.

Will eraan always be written together as one word?