Por and Para Both por and para are often translated as for into English; however, they cannot be used interchangeably. Each is used exclusively to express certain concepts. On the next two pages, explanations and examples are provided for each. Por is used to express the following concepts. -Motion or approximate location (through, around, along, by) Marta va por la avenida.    Marta is going down the avenue. Luis pasó por el teatro.    Luis went by the theatre. Juan salió por la ventana.    John went out the window. -Cause or motive or an action (because of, on account of, on behalf of) Llegué tarde por el tráfico.    I was late because of traffic. Lo hice por ti.    I did it on your behalf. -Means or unit of measure (by, for, per) Prefiero viajar por avion.    I prefer to travel by plane. °Ella va 200 km por hora!    She's going 200 km per hour! -In exchange for (money, barter) Le doy dos mil por el carro.    I"ll give you two grand for the car. -Period of time(during in, for) Estudiamos por la tarde.    We study in the afternoon. °Quiere visitar por un mes!    She wants to visit for one month! -In search of or for Vengo por ella a las dos.    I'm coming for her at two.