Breakdown of Penso che il cameriere sia stato scortese.
essere
to be
il cameriere
the waiter
pensare
to think
che
that (conjunction introducing a clause)
Questions & Answers about Penso che il cameriere sia stato scortese.
Why do we use the past subjunctive sia stato here instead of the present subjunctive sia?
The phrase Penso che expresses an opinion in the present, which triggers the subjunctive mood. Because the waiter's rudeness happened in the past, before your current thought, you must use the past subjunctive (sia stato) rather than the present subjunctive (sia). This relationship is often called anteriority.
How is sia stato formed, and why doesn't it use avere as the helper verb?
The past subjunctive is built using the present subjunctive of an auxiliary verb (essere or avere) plus the past participle. Here, the action verb is essere (to be). In Italian, essere always takes itself as its auxiliary. Therefore, you use sia (the present subjunctive of essere) and stato (the past participle of essere).
Does the adjective scortese change if we are talking about a female waitress?
No, it stays exactly the same. Adjectives ending in -e in the singular are used for both masculine and feminine nouns. If you were talking about a waitress, the sentence would be Penso che la cameriera sia stata scortese. Notice that the participle stata changes to match the feminine subject, but the adjective scortese does not!
Could I just use the normal past tense and say Penso che il cameriere è stato scortese?