keep up

Entry Definition
(walking alone) s/he lags behind, falls behind, cannot keep up
one who lags or falls behind, one who cannot keep up
s/he keeps up with it, catches up with it (car, etc.); s/he keeps up with the payments on it
(runner, walker, driver, etc.) s/he keeps up with h/, catches up with h/
(runner, walker, driver, etc.) s/he keeps up, catches up