proficiency

n.熟练，精通

productive, productivity, productivity agreement, prof, profanation, profane, profanely, profanity, profess, professed, professedly, profession, professional, professional foul, professionalism, professionally, professor, professorial, professorship, proffer, proficient, proficiently, profile, profit, profit and loss account, profit-margin, profit-sharing, profitability, profitable, profitably, profiteer, profiterole, profitless, profitlessly, profligacy, profligate, proforma, profound, profoundly, profundity,