- Why do you look so worried?- My MacBook Pro broke down and my paperunfinished since.A. w

问题补充：

- Why do you look so worried?

- My MacBook Pro broke down and my paperunfinished since.

A. was left

B. has left

C. left

D. has been left

答案：

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。