Por and para motion or a general location duration of an action reason or motive for an action object of a search means by which exchange or substitution unit of measure agent (passive voice)

Las palabras por y para son extraordinariamente confusas en español, porque tienen significados similares y usos tan diversos. No espere dominar los usos de por y para después de terminar esta lección. Tomará mucho más tiempo acostumbrarse a todas las instancias en las que se usa una en lugar de la otra.

En general, por y para ambos significan para o por. Solo para mostrar lo difícil que puede ser traducir la palabra "para" en inglés, mira las siguientes oraciones e intenta traducirlas en tu mente.

(im fluent in spanish so if you need other help on spanish just ask!)

which in english it means

"The words by and for are extraordinarily confusing in Spanish, because they have similar meanings and such diverse uses. Don't expect to master the uses of by and after you finish this lesson. It will take much longer to get used to all instances in which one is used instead of the other.

In general, by and for both mean for or by. Just to show how difficult it can be to translate the word "for" into English, look at the following sentences and try to translate them into your mind."

i have to listen to the audio to be able to answer your question.

i got it here  

fill in the blank with the correct answer. carlos and sofia and from toa baja to travel west along the coast.