[名词解释] 缩复作用

心电图纸以每秒25mm速度前移时，每小格代表() ["A．1秒","B．0.1秒","C．0.01秒","D．0.02秒","E．0.04秒"] 胎头拨露 衔接 潜伏期 下列哪种药物过量，可使QRS时间延长() ["A．奎尼丁","B．硝酸甘油","C．消心痛","D．吗啡","E．普萘洛尔"] 缩复作用