The Uses of Por

1. an exchange, such as with money.

Pago dos dolares por una taza de agua.- I pay two dollars for a cup of water

2. substitution or replacement

Trabajo por mi mejor amiga cuando ella esta enferma- I work for my best friend when she is sick

3. the reason for doing something

La profesora se triste por malas notas de sus estudiantes. - The professor is sad about her students' bad grades

4. an approximation of time

Mis amigos y yo nos hablamos por varias horas- My friends and I talked to each other for several hours.

5. a means of transportation

Mi amigo y yo comunicamos por correo electrónico. - My friend and I communicate by email.

6. where an action takes place

Mis padres corrieron por el lago. - My parents ran by the lake

The Uses of Para

1. deadlines or moments in time

Este reportaje es para el viernes. - This report is for Friday.

2. a destination

Salimos para Madrid a las nueve. - We leave for Madrid at nine.

3. the recipient of an action

Este regalo de boda es para los novios. - This wedding gift is for the couple.

4. a function or goal

Esta cámara digital sirve para sacar fotos. - This camera is for taking photos.

5. a purpose (in order to)

Llamé a mi amigo para contarle el secreto. - I called my friend to tell him a secret.

6. an opinion

Para ti, la amistad es muy importante. - For you, friendship is very important.