单项选择题
—We took a taxi and arrived at the station an hour earlier. —You ______ a taxi. Time was enough for you to go there by bus. A.needn't take B.needn't to take C.needn't have taken D.don't need take
单项选择题 功能性分流是指( ) A.肺动-静脉短路开放 B.部分肺泡V/Q比率增高 C.死腔气量增多 D.解剖分流增加 E.部分肺泡V/Q比率降低
单项选择题 9.1molH2O的质量为( ) A.18 B.18g C.18mg D.18kg
单项选择题 肺泡膜病变发生呼吸衰竭的主要机制是( ) A.肺泡膜厚度增加 B.肺泡膜面积减少 C.肺泡通气血流比例失调 D.呼吸功及耗能增加 E.血液与肺泡接触时间过短