Voted Best Answer
Apr 30, 2014 - 01:58 PM
As the two responses above indicate, it is not what comes after but what comes before. Basically, you just have to learn that any form of "ir" followed by a verb infinitive, take the "a." I am not sure about your example with "bailar" as I thought "despues" usually takes "de"; that is it would be "despues de bailar". Again though, it is a property of "despues" not "bailar." There are also other verbs other than "ir" that take prepositions before infinitives, such as "comenzar" that takes "a" and "terminar" that takes "de." But many take no preposition. For example, "I want to dance": "Quiero bailar." You just have to learn which is which, and with practice, it will come naturally.