ad lib

v (-bb-) [I] (infml 口) speak or act without preparation, esp when performing in public; improvise 临时讲话或表演（尤指当众）; 即席表演: The actress often forgot her lines but was very good at ad libbing. 那个女演员常忘台词, 却极擅长临时拼凑.

actor, actress, actual, actuality, actually, actuarial, actuary, actuate, acuity, acumen, acupuncture, acupuncturist, acute, acute angle, acute mark, acutely, acuteness, AD, ad hoc, ad infinitum, ad nauseam, ad-lib, adage, adagio, Adam, Adam's apple, adamant, adamantly, adapt, adapt oneself to, adapt to, adapt...to, adaptability, adaptable, adaptation, adaption, adaptive, adaptor, ADC, add,