--- Why? Tom your shirt is so dirty! --- Mum I my storeroom downstairs.A. cleanedB. hav

问题补充：

--- Why? Tom, your shirt is so dirty!

--- Mum, I my storeroom downstairs.

A. cleaned

B. have cleaned

C. was cleaning

D. have been cleaning

答案：

A. cleaned

B. have cleaned

C. was cleaning

(答案→)D. have been cleaning

解析：由上下文语境推出一直在做某事，同时对现在产生影响，衬衫脏。