1. once, as soon as

a. With que, introducing a full clause in the perfect aspect.

b. Introducing a reduced passive-voice clause consisting only of a subject plus a past participle phrase.

c. Introducing a reduced perfect-aspect clause consisting only of a subject plus a past participle phrase (provided that the verb is one that forms the perfect aspect with être).

d. Introducing a reduced clause in either of the above senses, consisting only a past participle phrase, its subject being implied.