What the A?
Why use A at the beginning of a sentence? It usually comes with the expression of an emotion such as gustar, to like.
Example:
ellas les gusta salir a comer
Correct answer; A ellas les gusta salir a comer
Is there a rule that I'm missing? Is it a matter of emphasis, like a mi me gusta?
2 Answers
In this case the "A" directs the action to the indirect object similar to the English "To". "Salir a comer" is the subject, "gusta" is the verb, and "ellas" is the indirect object. "Going out to eat pleases them."
It can also be an emphasis thing like you said, or depending on the context you may want to specify who you're talking about exactly.