下列哪一项不是清醒期间低血压的原因()。
A.前负荷降低
B.寒战
C.高热
D.外周阻力下降
E.心功能受抑制
参考答案:B
I met Julia the other day.It was the first time we each other since we graduated from school.
A.saw
B.had seen
C.did see
D.have seen
运输问题的求解结果中可能出现的是()。
A.惟一最优解
B.无穷多最优解
C.退化解
D.无可行解