题干
—— Why? Tom, your shirt is so dirty!
—— Mum, I ＿＿＿＿＿ my storeroom downstairs。
A：cleaned
B：have worked
C：was cleaning
D：have been cleaning
答案(点此获取答案解析）
D
A：cleaned
B：have worked
C：was cleaning
D：have been cleaning
和 
估一估．
