中心静脉压高,动脉压低()
A.心功能不全
B.血容量不足
C.心功能不全,外周阻力下降
D.体循环阻力与肺循环阻力均增加
E.血容量轻度不足
参考答案:B
—When did you return to Nanjing last Friday?
—It was not until midnight _______ it was snowing heavily. [ ]
A. that
B. before
C. while
D. when
学生在校期间有哪些义务?