Learn Dutch: De toerist vraagt bij de balie of de plattegrond gratis is. - The tourist asks at the counter if the map is free.

Because this sentence contains an indirect question starting with of (if or whether). The part after of is a subclause, which means the working verb gets pushed to the very end. So instead of the normal question order (is de plattegrond gratis?), the verb goes to the end: of de plattegrond gratis is.

Can of also mean "or"?

Yes! In normal statements, of means "or" (like koffie of thee). But when you use it to introduce a yes/no question inside another sentence, as we do here after the verb vraagt, it translates to "if" or "whether".

Why use plattegrond instead of kaart for "map"?

While kaart is a general word for a geographical map (like a map of a whole country), a plattegrond is specifically a detailed street map of a town, a floor plan of a building, or a layout of a specific place like a theme park. Since the tourist is likely asking for a city street map, plattegrond is the perfect word.

Why do we say bij de balie for "at the counter"?

The preposition bij is used to mean "at" or "near" a location. When you are standing at a desk, reception window, or counter to get help, bij is the standard preposition to use in Dutch.