— Did you go to his birthday party last night?      

— No, I____, but I had some extra work to finish.       [ ]

A. must have     

B. could have        

C. could          

D. ought to

应警惕有发生哪种并发症的危险

A．休克

B．血管神经损伤

C．腹部脏器伤

D．骨筋膜室综合征

E．下肢深静脉血栓