acumen

n. 敏锐，明智

action replay, action stations, actionable, activate, activation, active, active service (US also active duty), actively, activeness, activist, activity, actor, actress, actual, actuality, actually, actuarial, actuary, actuate, acuity, acupuncture, acupuncturist, acute, acute angle, acute mark, acutely, acuteness, AD, ad hoc, ad infinitum, ad lib, ad nauseam, ad-lib, adage, adagio, Adam, Adam's apple, adamant, adamantly, adapt,