Purpose, deadline, and cause

What you will practice

• Use para for purpose, a recipient, and a deadline.
• Use por for cause, exchange, duration, and movement through a space.
• Keep those seven examples from swapping prepositions.

Explanation

A small, clear split

para has three jobs here. Purpose takes para plus an infinitive: Estudio para aprender. A recipient also takes para: El regalo es para Ana. A deadline takes para plus the time something is due, and the day keeps its article: La tarea es para el lunes. These are not a cause, a price, or a path. If the sense is “in order to,” “meant for someone,” or “due,” you are in this group.

One example for each job

por has four jobs here, and each example shows only one. Cause is Gracias por tu ayuda: the thanks exist because of the help. Exchange is Pago veinte pesos por el libro: money given for the book. Duration is Estudié por dos horas: the studying lasted two hours. Movement through a space is Caminamos por el parque. The table keeps all seven sentences with the preposition each one needs.

Do not swap them

Do not trade the prepositions inside these patterns. Estudio por aprender is not the purpose sentence. Purpose here is Estudio para aprender. Gracias para tu ayuda is not the cause sentence. Cause here is Gracias por tu ayuda. Caminamos para el parque can point toward a destination, which is not the “through” meaning taught with por. Other uses of both words exist in the language. They are outside this lesson, and none of the exercises depends on them.

Examples

1. Estudio para aprender.I study in order to learn.
2. El regalo es para Ana.The gift is for Ana.
3. Gracias por tu ayuda.Thanks for your help.
4. Estudié por dos horas.I studied for two hours.
5. Caminamos por el parque.We walked through the park.

Common mistakes

• A deadline in this lesson is para plus a moment, as in para el lunes. It is not por.
• por dos horas answers “how long.” It does not name the reason for studying.