现在完成时的所有知识,特别是短暂性动词与延续性动词,since 能不与短暂...答:for, since, so far, ever, never, just, yet, till / until, up to now, in past years, always, 不确定的时间状语 3)现在完成时可表示持续到现在的动作或状态,动词一般是延续性的,如live, teach, learn, work, study, know. 过去时常用的非持续性动词有come, go, leave, start, die, finish, ...