grammar.conjunctions.cause
Because: porque, como, ya que, pues
Porque follows the result (no fui porque llovía); como leads with the cause (como llovía, no fui); ya que / puesto que / dado que are formal 'since'.
grammarB1v0.1.0
Explicación
Position rules them: porque mid-sentence, como sentence-initial only. *Porque llovía, no fui sounds off; flip to como or move porque after.
Por + infinitive compresses cause with same subject: lo multaron por estacionar mal. Distinguish porque (because), por qué (why?), porqué (the noun 'reason'), por que (rare, 'for which').
Ejemplos
Como no contestaste, vine directo.
Since you didn't answer, I came straight over.
Since you didn't answer, I came straight over.
Región: global
Cerramos temprano porque era feriado.
We closed early because it was a holiday.
We closed early because it was a holiday.
Región: global