lag /læɡ/ I. vi. 落后，走得慢：Some of the runners in the race began to lag. 比赛中有些运动员开始掉队。Business is lagging critically in that sector. 那个部门的业务严重落后。lag behind 落后：The lame child lagged far behind. 那个跛足的孩子远远落在后面。 ‖II.n. ［u］延迟(有时与a连用)：Bad weather caused a lag in the scheduled activities. 天气不好延误了业已安排好的活动。The work must go forward without lag. 这项工作必须毫不迟延地进行。