-- Why do you look so worried ?-- My MacBook Pro broke down and my paper unfinished ever

问题补充：

-- Why do you look so worried ?

-- My MacBook Pro broke down and my paper unfinished ever since.

A. left

B. was left

C. has been left

D. has left

答案：

A. left

B. was left

(答案→)C. has been left

D. has left

解析：考查时态：句意：--你为什么看起来这么担心？-- 我的MacBook Pro坏了，我的论文自从那时还留在那里没有完成。从ever since可知是现在完成时，从paper和leave的关系，可知是被动。选C。