The verb estar is frequently followed by a preposition in ways that are uncommon with the English equivalent "to be." Here are some of the common combinations:
Estar de: Temporary situations including roles, employment and emotions are often expressed using estar de. Some examples:
- La red social más popular está de cumpleaños. The most popular social network is having a birthday.
- No te pongas serio. Estaba de broma. Don't take it seriously. He was joking.
- Estoy de acuerdo contigo. I agree with you.
- Mi hermano está de chofer. My brother is working as a driver.
- Estamos de vacaciones. We're on vacation.
- ¿Qué tipos de vestidos están de moda? What types of clothing are in style?
- Los Smith están de aniversario. It's the Smiths' anniversary.
- Los conductores están de huelga. The drivers are on strike.
- El jefe está de un humor muy feo. The boss is in a very ugly mood.
Estar con: In addition to indicating who someone is with, estar con can be used to indicate illnesses, what a person is wearing and other characteristics:
- Tengo un amiga que está con la influenza porcina. I have a friend who has swine flu.
- Hay días que estoy con dolor constante. There are days I'm in constant pain.
- Estaba con pantalones cortos y una playera blanca. He was wearing short pants and a white T-shirt.
- Cuando estamos con prisa, es fácil pasar por alto algunas prácticas de seguridad. When we're in a hurry, it's easy to overlook some safety measures.
- La carne estaba con mal olor. The meat smelled bad.
- Estamos con duda sobre estos medicamentos. We are in doubt about these medications.
Estar sin: Estar sin is used much like estar con but with the opposite meaning. (Of course, it can also mean "to be without."):
- De momento estoy sin dolor. At the moment I'm not in pain.
- Unas 8.000 personas estaban sin hogar en la ciudad. There are some 8,000 homeless people in the city.
- Estoy sin dinero y sin amigos. I am penniless and friendless.
Estar en: Estar en is often used much like "to be in."
- Está en buena condición la carretera. The road is in good condition.
- Las autoridades locales estaban en conflicto con los operadores de turismo. The local authorities were in conflict with the tourism operators.
- Esta página web está en construcción. This web page is under construction.

