—What has happened to Tom?  

—He is so tired after ______ walk.[ ]

A. three hours  

B. three hours'  

C. three hour's  

D. three hour

患者女性，35岁。功能性子宫出血1年，血红蛋白低于5g/dl，则()

A．出现发绀

B．不出现发绀

C．出现休克

D．出现抽搐

E．禁忌手术