—You seem tired David.—Yes. I all day long and can’t wait to go to bed now.A. am working

问题补充：

—You seem tired, David.

—Yes. I all day long and can’t wait to go to bed now.

A. am working

B. had been working

C. have been working

D. was working

答案：

A. am working

B. had been working

(答案→)C. have been working

D. was working

解析：考查时态。根据句意可知用现在完成进行时，句意:——戴维，你看起来很累。——是的，我工作了一整天，现在都迫不及待的的上床睡觉了。