If you know what you’re . escoge la preposición correcta de por o para, para completar la frase. select the correct preposition, por or para, in order to complete the sentence. mi pobre hermano está enfermo y no puede ir al concierto este fin de semana. yo voy a ir él para no perder el dinero.

Mi pobre hermano está enfermo y no puede ir al concierto este fin de semana. Yo voy a ir por él para no perder el dinero.

Explanation:

The translation for these sentences is:  

My poor brother is sick and cannot go to the concert this weekend. I'm going to go instead of him so we don't lose money.

Por is a preposition. Prepositions give us information abou other words in the sentence (like time and place). Much like para, both prepositions share similar meanings and diverse usages. Por can generally be translated to for (Lo hice por él / I did it for him) but that is not always the case since para can be used like that too.

In the sentence provided by the exercise, por means instead of. If I had used para in this particular sentence (Yo voy a ir para él para no perder dinero) it would have meant "for him" and not "instead of him".