prius respondēs quam rogō, you answer before I ask;
nihil contrā disputābō priusquam dīxerit, I will say nothing in opposition, before he speaks.
2. Sometimes the Perfect, especially after negative clauses; as,—
nōn prius jugulandī fīnis fuit, quam Sulla omnēs suōs dīvitiīs explēvit, there was no end of murder until Sulla satisfied all his henchmen with wealth.
B. WITH THE SUBJUNCTIVE.
[292]. Antequam and priusquam take the Subjunctive to denote an act as anticipated.
1. Thus the Subjunctive may denote—
a) An act in preparation for which the main act takes place; as,—
priusquam dīmicārent, foedus īctum est, i.e. in anticipation of the fight, a treaty was struck.
By an extension of this usage, the Subjunctive is sometimes used of general truths, where the anticipatory notion has faded out; as,—
tempestās minātur antequam surgat, the tempest threatens before it rises.