二者都可以,以下是它们之间的关系与区别:
till和until都表示“直到……为止”,主句用延续性动词,主句和从句都用肯定式;表示“直到……才”时,主句用终止性动词,从句用肯定式,主句用否定式.until较till正式,until引导的时间从句可以放在句首.go straight on until you come to the post office and then turn left.一直向前走到邮局再向左转.she won’t go away till you promise to help her.在你答应帮助她之前,她不会走的.until you told me,i had heard nothing of when happened.直到你告诉我,我才知道发生了什么事.