由喷射泵自身性质决定了其最大压缩比为()左右。
A.3
B.6
C.9
D.12
参考答案:D
His spare time is made full use __ law. 31-35 DACAB
A.to study
B. study
C.of studying
D.of to study
左房增大最早出现的X线征象是()
A.左心缘第三弓突出
B.右心缘双边阴影
C.右心缘双房影
D.右前斜位食管吞钡左房压迹增加
E.左前斜位左主支气管变窄、抬高