These days Andrew has spent as much time as he________the final exam. [      ]

A. could prepare for  

B. could preparing for

C. could prepared for    

D. prepared for

麻黄碱主要用于

A．神经性休克
B．轻症支气管哮喘
C．心源性休克
D．房室传导阻滞
E．过敏性休克