I’m most awfully grateful to you. I can’t think what I without you.A. could doB. would do

问题补充：

I’m most awfully grateful to you. I can’t think what I without you.

A. could do

B. would do

C. should have done

D. must have done

答案：

A. could do

B. would do

(答案→)C. should have done

D. must have done

解析：考查情态动词。句意：我非常的感激你，我认为没有你我本不应该完成的。should have done 本应该做某事而事实上没有做，shouldn’t have done 本不应该做某事而实际上做了。所以选C。