drop off

减弱，减少

driving licence, driving school, driving-belt, driving-licence, driving-test, driving-wheel, drizzle, drizzly, drogue, drogue-parachute, droll, drollery, dromedary, drone, drool, droop, droopy, drop, drop by, drop by/in, drop on, drop out, drop over, drop to one's knees, drop-goal, drop-hammer, drop-forge, drop-press, drop-kick, drop-out, droplet, dropout, dropper, droppings, dropsical, dropsy, dross, drought, drove, drover, drown, drowse,