Learn Portuguese (Portugal): Quanto quer o senhor pagar?

Quanto changes to match the gender and number of a noun if it is asking about something specific (like Quantas casas for 'how many houses'). But here, it asks about the action of paying. When quanto relates directly to a verb, it acts as an adverb and always stays in its default masculine singular form.

Why is o senhor in the middle of the sentence instead of at the beginning?

In Portuguese questions, it is very common to put the conjugated verb (quer) right after the question word (Quanto), pushing the subject (o senhor) after it. You will also often hear Quanto o senhor quer pagar?, but splitting the verbs like in this sentence is a very natural way to ask questions in Portugal.

Why does this sentence use o senhor to mean 'you'?

In Portugal, o senhor (literally 'the sir') is the standard formal way to say 'you' to a man, such as a customer in a shop or someone older than you. It uses the same 3rd-person verb endings as ele (he), which is why the verb is quer (wants).

Why is pagar left in its dictionary form instead of being conjugated?