a quarter till [sth], a quarter 'til [sth] (US), a quarter to [sth], quarter to [sth] (UK)exprexpression: Prepositional phrase, adverbial phrase, or other phrase or expression--for example, "behind the times," "on your own."
(15 minutes before the hour)
差十五分钟到…（点）
I'll meet you at a quarter till one... in the afternoon, of course.