I was standing behind him and I did see Sandra handing the letter to Joe.

A．hand

B．has handed

C．handed

D．was handing

小肠大部分切除，腹泻的发病机制为（）

A．肝硬化腹水 

B．急性胃穿孔致腹膜炎 

C．胰腺囊肿 

D．癌症晚期恶病质 

E．腹白线疝