Esos libros están en oferta.

Those books are on sale.

Breakdown of Esos libros están en oferta.

• el libro: the book
• estar: to be
• esos: those
• en oferta: on sale

Questions & Answers about Esos libros están en oferta.

Why is it están and not son?

Spanish uses estar for temporary states or conditions. Being “on sale” is temporary, so están fits. Ser is for inherent traits or for events.

• Correct: Esos libros están en oferta.
• Contrast: Esos libros son baratos. (inherently cheap)
• Note: Esos libros son en oferta is incorrect; ser + en is for events (e.g., La reunión es en la sala).

What’s the difference between esos, estos, and aquellos?

They’re demonstratives that mark distance:

• estos = these, near the speaker.
• esos = those, near the listener or at medium distance.
• aquellos = those (over there), far from both. In much of Latin America, speakers use ese a lot for most “that” cases, and reserve aquel for extra distance or to refer back to something mentioned earlier.

Why the preposition en? Can I use de, a, or por?

• estar en oferta is the most standard, pan-Hispanic way to say “to be on sale (discounted).”
• estar de oferta is also very common in Latin America and usually means the same thing.
• estar a la venta means “to be for sale (available to buy),” not necessarily discounted.
• por oferta is not used for this meaning.