- Why do you look so worried?
- My MacBook Pro broke down and my paper unfinished since.
A. was left
B. has left
C. left
D. has been left
网友回答
A. was left
B. has left
C. left
(答案→)D. has been left
解析：考查时态。since后省略了“it broke down”，since+含有一般过去时的句子，与现在完成时连用；排除A、C；my paper和leave是动宾关系，用被动语态，故选D。