三尖瓣位于()。
A.左房室口
B.右房室口
C.肺动脉口
D.主动脉口
E.冠状动脉口
参考答案:B
_____ Saturday morning, his father usually gets up _____ eight-thirty. [ ]
A. At; at
B. On; in
C. At; in
D. On; at
骨盆骨折最危险的并发症是()
A.骨盆腔内出血
B.膀胱破裂
C. * * 断裂
D.直肠损伤
E.骶丛神经损伤