Por vs Para
I am a little bit confused, when I can use POR and when PARA... Can anyone explain me that?
I found this in the Web (Encontre esto por la Web)
"Por" has many uses, and so it is the more problematic of the two.
Rule: to express gratitude or apology Model: Gracias por la ayuda. (Thanks for the help.)
Rule: for multiplication and division Model: Dos por dos son cuatro. (Two times two equals four.)
Rule: for velocity, frequency and proportion Model: Voy al restaurante cinco veces por semana. (I go to the restaurant five times per week.)
Rule: meaning "through," "along," "by" or "in the area of" Model: Andamos por el parque. (We walk through the park.)
Rule: when talking about exchange, including sales Model: Él me dio diez dólares por el libro. (He gave me ten dollars for the book.)
Rule: to mean "on behalf of," or "in favor of," Model: No voté por nadie. (I didn't vote for anyone.)
Rule: to express a length of time Model: Yo estudié por dos horas. (I studied for two hours.)
Rule: to express an undetermined, or general time, meaning "during" Model: Se puede ver las estrellas por la noche. (One can see the stars during the night.)
Rule: for means of communication or transportation Model: Prefiero viajar por tren y hablar por teléfono. (I prefer to travel by train and speak by phone.)
Rule: in cases of mistaken identity, or meaning "to be seen as" Model: Me tienen por loco. (They take me for crazy.)
Rule: to show the reason for an errand (with ir, venir, pasar, mandar, volver, and preguntar) Model: Paso por ti a las ocho. (I'll come by for you at eight o'clock.)
Rule: when followed by an infinitive, to express an action that remains to be completed, use por + infinitive Model: La cena está por cocinar. (Dinner has yet to be cooked.)
Rule: to express cause or reason Model: El hombre murió por falta de agua. The man died for lack of water.
Rule: "estar por" means to be in the mood, or inclined to do something Model: Estoy por tomar café. (I'm in the mood for drinking coffee.)
Rule: in passive constructions Model: El libro fue escrito por Octavio Paz. (The book was written by Octavio Paz.)
"Para" -- in contrast, has relatively fewer uses.
Rule: to indicate destination Model: El hombre salió para Madrid. (The man left for Madrid.)
Rule: to show the use or purpose of a thing Model: El vaso es para agua. (The glass is for water.)
Rule: to mean "in order to" or "for the purpose of" Model: Para hacer una paella, primero dore las carnes. To make a paella, first sauté the meats.
Rule: to indicate a recipient Model: Este regalo es para ti. (This gift is for you.)
Rule: to express a deadline or specific time Model: Necesito el vestido para el lunes. (I need the dress by Monday.)
Rule: to express a contrast from what is expected Model: Para un niño lee muy bien. (For a child, he reads very well.)
Rule: "estar para" to express an action that will soon be completed Model: El tren está para salir. (The train is about to leave.)
This one is nice too: http://www.spanishnewyork.com/automatic/porpara.php
Don't worry about getting it perfect just yet--it's something that a formal course will circle back around to multiple times over the years. Your meaning will usually be understood if you use the wrong one. I just memorized it when I had Spanish in high school and it was a struggle. Now, many years later (albeit with a break!), it has become fairly natural. Practice--and above all, exposure.