When to use “POR” and “PARA” in Spanish
By Uri S. Quintal.
Prepositions in Spanish are used almost in every sentence but, there are two ones that cause a lot of problems when students are trying to learn the language. Prepositions por and para challenge Spanish students to be very careful with their usage because both words mean “for” in English. In this case, preposition POR is considerably more common, so in theory, students might be able to get away with just memorizing the uses for PARA and then use POR for everything else. But, getting to know the specific ways and situations in which they should be used is also the best way to differentiate both prepositions.
Spanish preposition POR is used to indicate:
Native Spanish speakers use preposition POR when they refer to motion or a place in which the subject of the sentence is making an action at a specific moment, for example, Ellos caminan por las calles. (They walk through the streets.)
Preposition POR is also used to indicate how a specific action is or has been done by the subject of the sentence, for example, Ella envio la carta por correo aéreo. (She sent the letter by air-mail.)
3. In exchange for/substitution:
Another situation in which preposition POR is used is when the subject of a sentence is doing something in exchange for something, for example, El me dio dos lapices por mi pluma (He gave me two pencils for my pen) or in substitution of someone like, Voy a hacerlo por tí. (I’m going to do it for you.)
4. Duration of an action:
When indicating how long an action was happening the best preposition to use is POR, because it explains and supports the information given in a sentence by letting us know the duration of an action, for example, Solamente trabaje por una hora. (I only worked for an hour.)
5. Indefinite time period:
Preposition POR is also used to indicate and describe a specific period of time...