Cause
Why does something happen or turn out this way?
Significado
A cause explains why something happens or why a situation is as it is. It may be an earlier event, a circumstance, or someone's reason for acting. Languages use linking words, endings, or context, and some have no separate cause marker. Unlike Purpose, Cause explains what brings about an event, not what someone hopes to achieve.
Como identificar
Find the part that answers why the event happened or why the situation is as described.
Na tua língua materna
Porque introduces a statement explaining why something happens, while por causa de introduces a noun naming the cause. Como can introduce a reason at the beginning of a sentence, often presenting it as background for what follows. Já que also gives a reason that the speaker treats as established.
A padaria fechou mais cedo porque faltou luz.
Por causa da chuva, o jogo foi adiado.
Como o ônibus demorou, fui a pé.
Como gives a reason here, not a description of how something happened.
Na tua língua de aprendizagem
English uses because to introduce a reason expressed as a full clause, a part with its own subject and verb. Because of comes before a noun or a noun phrase, a group of words built around a noun. Since and as can also introduce reasons, though they have other meanings in other contexts.
I took a taxi because I was late.
Because introduces a reason with its own subject and verb.
The game was canceled because of the rain.
Because of is followed by a noun phrase, not a full clause.
Since the store is closed, we'll come back tomorrow.
Since gives a reason here; it does not mark a starting time.
Learners whose language uses one expression before both nouns and full clauses may confuse because and because of. Learners whose language regularly pairs cause and result markers may use because and so together in a sentence where English normally uses just one.