第13题:[单选题]2.The marginal rate of transformation (MRT) of X for Y refers to: A.A.the amount of Y that a nation must give up to produce each additional unit of X B.B.the opportunity cost of X C.C.the absolute slope of the production frontier at the point of production D.D.all of the above 参考答案:D
第15题: [单项选择]脉搏减慢可见于 A. 缺铁性贫血 B. 动脉粥样硬化 C. 心功能不全 D. 失血性休克 E. 颅内压增高 参考答案:E 答案解析:缓脉是指成人脉率低于60/分,见于颅内压增高、房室传导阻滞、甲状腺功能减退、阻塞性黄疸的病人,或服用某些药物如地高辛、普尼拉明、利舍平、普萘洛尔等患者。正常人可出现生理性窦性心动缓慢,多见于运动员。