effectively◼◼◼(in an efficient or effective manner; with powerful effect) adverb [UK: ɪ.ˈfekt.ɪv.li] [US: ɪ.ˈfekt.ɪv.li]That book helps you to write effectively. = Ce livre vous aide à écrire efficacement.
efficiently◼◼◻(in an efficient manner) adverb [UK: ɪ.ˈfɪʃnt.li] [US: ə.ˈfɪ.ʃənt.li]John runs the family business very efficiently. = Jean gère très efficacement l'entreprise familiale.