下述哪些是肺动脉高压的病因（）
A.慢性缺氧
B.肺血管阻力增加
C.血黏度降低
D.肺小动脉痉挛
E.左心功能不全
参考答案：A, B, D
为预防门静脉高压症术后感染，应用广谱抗生素，用药时间一般开始于术前
A．2d
B．4d
C．6d
D．8d
E．10d
Amy is very friendly. She is easy to ______. [ ]
A. begin with
B. get along
C. talk about
D. get along with
