Prepositions and Prepositional pronouns
I am confused still occasionally about whether to use "a" or "en", or "de" and "con" for that matter. The lesson on Spanishdict makes clear the use of "por" and "para", though. Also, what do pronoun subjects of prepositions look like? Is there a lesson on these? If so, it is not necessary to answer this question here.
2 Answers
Prepositions in Spanish often differ from English. You have to read, make flash cards, and memorize. For example, in English we listen to the music, but in Spanish we say escuchar la música, no preposition needed.
This might help:
[http://www.spanishdict.com/answers/198473/nominative-objects-of-prepositions-#q198473]