房颤发生的心外原因首先考虑（）
A.甲状腺机能亢进症
B.多发性硬化症
C.肺栓塞
D.电解质紊乱
E.脑中风
参考答案：A
下列哪种结构没有参与会阴境界的围成（）
A.耻骨下支
B.尾骨尖
C.耻骨联合下缘
D.坐骨棘
E.骶结节韧带
________ something wrong with the machine, I am afraid.
A．There seems to have
B．There seems to be
C．He seems to be
D．It seems to be
