第18题: [单项选择]A) Because they arrived there too late. B) Because they can’t stand seeing the tragic scene. C) Because the police didn’t allow them to see it. D) Because they should not destroy the scene. 参考答案:C 答案解析:[听力原文] Why were Nikki’s parents prevented from seeing Nikki’s dead body on the road scene [答
第19题: [单项选择]正常情况下肺弹性阻力的主要来源是() A. 肺泡表面张力 B. 肺表面活性物质 C. 气道阻力 D. 肺组织本身的弹性阻力 E. 惯性阻力 参考答案:A