第3题: [单项选择]关于房室结折返性心动过速的表述,正确的是 A. 快慢型约占90% B. 心房和心室是折返环的重要组成部分 C. 房室结内或房室结周围存在双径路是形成折返的基础 D. 通常快径路的不应期较短,慢径路的不应期较长 E. 最早的逆传心房激动点位于冠状静脉窦远端 参考答案:C 答案解析:[解析] 房室结折返性心动过速的类型以慢快型最常见,快慢型和慢慢型较少见。通常快径路传导较快,不应期较长,慢径路传导较慢,不应期较短。心动过速时折返环为快、慢径路之间的折返。心内电生理检查可见逆传心房
第25题: [单项选择]What conclusion can we draw from this conversation A. Public buses are fast and cheap. B. Parking is becoming a big problem. C. Subway trains are even safer than taxis. D. Taxis are more convenient than buses. 参考答案:B 答案解析:M: Many people prefer taking public buses or the subway, or even taxies because parking is getting t