2.按时限分实义动词又分成延续性动词和非延续性动词（短暂性动词）
延续性动词动作可以延续，可以与一段时间连用。如：live, study, work, stay, keep, have等。
非延续性动词（短暂性动词）动作瞬间完成，不能与一段时间连用。如：finish, come, open, bring, buy等]
例：The evening news comes on at seven o' clock and ________ only thirty minutes.
A. keeps B. continues C. finishes D. lasts
