第4题: [单项选择]肺动脉增宽:() A. X线胸片显示主动脉结增宽,肺动脉段凹陷,右室增大,肺血减少 B. X线胸片显示主动脉结正常,肺动脉段突出,右室增大,肺血减少 C. X线胸片显示主动脉结缩小,肺动脉段突出,右室增大,肺血增多 D. X线胸片显示主动脉结增宽,肺动脉段突出,左室增大,肺血增多 E. X线胸片显示主动脉结缩小,肺动脉段突出,左室增大,肺血增多 参考答案:B
第20题: [单项选择]While crossing the mountain area, all the men carried guns lest they ______ by wild animals. A. should be attacked B. had been attacked C. must be attacked D. would be attacked 参考答案:A 答案解析:[解析] 本题考查虚拟语气。分析题干可知,句中有一个由lest引导的状语从句。在由lest引导的目的状语从句中,需要使用虚拟语气,意为“以防,以免”,其谓语动词多由“should+动词原形”构成,因此