血容量严重不足()
A.中心静脉压低,动脉压低
B.中心静脉压低,动脉压正常
C.中心静脉压高,动脉压低
D.中心静脉压高,动脉压正常
E.中心静脉压正常,动脉压低
参考答案:A
When _______how a statue from distant Greece could have appeared in China, researchers explained that no doubt this was a result of Alexander the Great’s influence.
A.to be asked
B.asking
C.asked
D.being asked
测定变量之间相关密切程度的代表性指标是()
A.估计标准误
B.两个变量的协方差
C.相关系数
D.两个变量的标准差