Learn Spanish (Latin America): Tardamos mucho por las obras. - We take a long time because of the roadworks.

In this sentence, por is used to show the cause or reason for something, translating to "because of" or "due to." They are taking a long time because of the roadworks. This is one of the main uses of por.

Why can't I use porque instead of por to say "because"?

The word porque means "because" and must be followed by a phrase with a verb (like porque hay obras, meaning "because there are roadworks"). Since las obras is just a noun, you use por, which translates to "because of."

I thought obras meant "works" of art. Why does it mean "roadworks" here?

While obras can mean works of art or theater plays, in everyday street contexts it refers to construction sites, building works, or roadworks. You will often see street signs saying en obras (under construction).

The translation says "we take a long time." How does tardamos mucho mean all of that without a word for "time"?

The Spanish verb tardar specifically means "to take time" or "to be delayed." Because the idea of "time" is already built into the verb itself, simply adding mucho (a lot) creates the full meaning "to take a long time." You don't need a word-for-word translation from English!