[单项选择]What is the best title for the text A. How to Play Chess B. Play Chess With Lens C. Relationship Between Chess-playing and Lens-designing D. What Insight From Lens to Chess
第13题: [单项选择]风湿性心脏病严重二尖瓣狭窄突发大咯血是由于() A. 肺毛细血管破裂 B. 合并肺结核 C. 急性肺水肿 D. 支气管静脉破裂 E. 合并支气管扩张 参考答案:D 答案解析:严重二尖瓣狭窄突然咯大量鲜血可作为首发症状。支气管静脉同时回流入体循环静脉、肺静脉,当肺静脉压突然升高,黏膜下淤血,扩张且壁薄的支气管静脉可破裂引起大咯血。咯血后肺静脉压减低,咯血可自止