在……发生之前
Merriam-Webster Online Dictionary
prior to (preposition)in advance of - before
Merriam-Webster Online Thesaurus
prior to (preposition)earlier than
SYNONYMS:
afore, ahead of, ere, fore ( 'fore), of, previous to, prior to, toRELATED WORDS:
till, until, up toNEAR ANTONYMS:
next, next to, since