acute

a.剧烈的；敏锐的；成锐角的；尖的，高音的

activate, activation, active, active service (US also active duty), actively, activeness, activist, activity, actor, actress, actual, actuality, actually, actuarial, actuary, actuate, acuity, acumen, acupuncture, acupuncturist, 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, adapt oneself to, adapt to, adapt...to,