下列哪项不是逆行肾盂造影的禁忌证 ()
A. * * 狭窄
B.严重的肾结核
C.泌 * * 急性炎症
D.全身情况衰竭者
E.严重血尿和肾绞痛
参考答案:B
The problem is so difficult that ______ students can work it out. [ ]
A. a few
B. a little
C. few
D. little
P-R间期正常值为()
A.0.01s
B.0.11s
C.0.12s
D.0.11~0.17s
E.0.12~0.20s