下列哪项引起左室压力负荷过重（）。
A.高血压
B.二尖瓣关闭不全
C.主动脉瓣关闭不全
D.甲状腺功能亢进
E.贫血
参考答案：A
性病的传播途径有哪些？
Benefits of implementing EDI include( ).
A．eliminating the need to reenter data
B．reducing transmission errors
C．avoiding printing and mailing costs
D．all of the above
