efficiency

a.有效的，生效的

efface, effacement, effect, effect on, effective, effectively, effectiveness, effectual, effectually, effeminacy, effeminate, effeminately, effervesce, effervescence, effervescent, effete, effeteness, efficacious, efficaciously, efficacy, efficient, efficiently, effigy, effing, efflorescence, efflorescent, effluent, effluvia, effort, effortless, effortlessly, effortlessness, effrontery, effulgent, effusion, effusive, effusively, effusiveness, EFL, EFTA (also Efta),