问题
选择题
I really don't know how to thank you, but for your help, I ________ my lost necklace.
A．couldn't have found
B．mustn't have found
C．couldn't find
D．wouldn't find
答案
答案：A
A 句意：我真的不知道该怎样感谢你，没有你的帮助，我不可能找到我丢失的项链。couldn't have done表示对过去情况的否定推测，意为“不可能”。