W: (v) lag [Related to: laggard, lagger] (hang (back) or fall (behind) in movement, progress, development, etc.)
W: (v) trail [Related to: trailer] (move, proceed, or walk draggingly or slowly) "John trailed behind his class mates"; "The Mercedes trailed behind the horse cart"
W: (v) trail [Related to: trailer] (to lag or linger behind) "But in so many other areas we still are dragging"