— Why David you look so tired!— Well I an article and I must finish it tomorrow.A. was

问题补充：

— Why, David, you look so tired!

— Well, I an article and I must finish it tomorrow.

A. was writing

B. will be writing

C. have been writing

D. have written

答案：

A. was writing

B. will be writing

(答案→)C. have been writing

D. have written

解析：考查时态，句意：大卫，你为什么看起来这么累呢？哦，我一直在写文章我必须明天完成。根据语境动作是从过去开始一直持续到现在还要持续下去，故用现在完成进行时，选C。