quick: stresses instancy of response and is likely to connote native rather than acquired power: a ~ mind.  (acquired从外部获得的、习得的，不是本身就具有的，如Acquired Immuno Defect Syndrome获得性免疫系统缺陷症）   （instant立即implies what happens immediately，如I'll be back in an instant我立即回来，如Mr Porter's book was an instant hit波特先生的书一经推出立即大受欢迎，这个词还表示速溶方便的，如instant coffee/noodles速溶咖啡/方便面)


prompt: is more likely to connote training and discipline that fits one for instant response: the ~ response of emergency medical technicians.


ready: suggests facility and fluency in response: backed by a pair of ~ assistants.   （fluent形容人说话流利，有两层意思1是说话轻松，2是说的内容多，如a fluent English speaker一个说流利英语的人）


apt: stresses the possession of qualities, such as high intelligence, a particular talent, or a strong bent, that make quick effective response possible: an ~ student.


quick快速: 表示立即响应，常表示天生而非习得的能力，prompt快速: 暗示由于培训训练使人能立即响应(如例句中的医疗团队)，ready准备就绪:  表示能够轻松流畅的响应，apt聪明机灵: 强调具有智商天赋爱好等特质，所以能够快速响应


记忆方法: 1）首字母PARQ的发音是park公园<==迅速          体育锻炼不但增强记忆力，还提升大脑抗压能力，使人反应更迅速

               2）迅速的意思是反应快不迟疑犹豫mean able to respond without delay or hesitation or indicative of such ability.   respond和answer, reply的区别是，respond一般表示"快速"反应implies quick reaction，如本组4个词的解释中都有这个词.