Saremmo rimasti in banca più a lungo se lo sportello fosse stato aperto anche nel pomeriggio.

Saremmo rimasti is the condizionale passato (past conditional) of rimanere.

• It’s formed with the present tense of the auxiliary essere (saremmo) + the past participle rimasti.
• The past participle agrees in gender and number with the subject (rimasti for a masculine or mixed group; rimaste for a feminine group).
  Use it to talk about hypothetical or unfulfilled actions in the past.

Rimanere is an intransitive verb that always takes essere as its auxiliary in compound tenses.

• With essere, the past participle must agree with the subject:
  • io sono rimasto/rimasta
  • noi siamo rimasti/rimaste
    Hence, saremmo rimasti ends in -i for a masculine (or mixed-gender) group.

Fosse stato aperto is the trapassato congiuntivo (pluperfect subjunctive) in the passive voice.

• Formed with the imperfect subjunctive of essere (fosse) + stato
  • past participle aperto.
• It’s used after se in a counterfactual (unreal) past conditional to show something did not happen but is being imagined.

The passive form emphasizes lo sportello (the counter) being open, without specifying who did it.

• Passive: se lo sportello fosse stato aperto
• Active equivalent: se avessero aperto lo sportello
  Both convey the same idea; the passive is common when the agent is unknown or irrelevant.

In Italian, certain institutions and businesses typically use in to indicate location:

• in banca = “at the bank.”
  Although you could say alla banca centrale (at the central bank), for everyday banking you normally say in banca.

Più a lungo means “longer” in terms of duration.

• lungo as an adjective means “long” (length).
• a lungo (with a) makes it adverbial: “for a long time.”
• più
  • a lungo = “for a longer time” → “longer.”

Anche nel pomeriggio means “also in the afternoon.”

• anche adds “too” or “as well.”
• It expands the condition: the counter would have been open not just in the morning but also in the afternoon.

This structure is used for past counterfactuals (third‐type conditionals):

• Main clause: condizionale passato (e.g., saremmo rimasti)
• Se-clause: trapassato congiuntivo (e.g., se lo sportello fosse stato aperto)
  It describes a hypothetical past situation and its unrealized consequence.