Breakdown of Ellos ya habían pasado la aduana.
ellos
they
pasar
to come in / to pass / to spend / have (time)
ya
already / now (right now)
haber
(auxiliary) have
Questions & Answers about Ellos ya habían pasado la aduana.
Why use habían pasado instead of the preterite pasaron?
Habían pasado is the past perfect tense (meaning "had passed" or "had gone through"). You use it to show that an action was completely finished before another action in the past. Even though the second action isn't mentioned in this sentence, using the past perfect implies they got through customs before something else happened, like boarding their flight.
In English we say "had already gone." Can I put ya between habían and pasado in Spanish?
No, in Spanish you can almost never put a word between the helping verb (habían) and the past participle (pasado). Adverbs like ya (already) are usually placed right before the helping verb, which is why it is ya habían pasado.
Why is it la aduana with the article "la", when in English we just say "through customs"?
Spanish uses definite articles (el, la, los, las) much more often than English does, especially for locations, institutions, and general concepts. When talking about going through a checkpoint like customs or security, you always include the article: pasar la aduana.
Does pasar translate to "go through" here? I thought it meant "to pass."