—— Why? Tom, your shirt is so dirty!

—— Mum, I ＿＿＿＿＿ my storeroom downstairs。

A.cleaned     B.have worked  C.was cleaning     D.have been cleaning

.—— Why? Tom, your shirt is so dirty!

—— Mum, I ＿＿＿＿＿ my storeroom downstairs。

A.cleaned     B.have worked

C.was cleaning     D.have been cleaning

—— Why? Tom, your shirt is so dirty!

  —— Mum, I ＿＿＿＿＿ my storeroom downstairs。

A. cleaned      B. have worked  C. was cleaning     D. have been cleaning

—— Why? Tom, your shirt is so dirty!

—— Mum, I ＿＿＿＿＿ my storeroom downstairs。

A.cleaned B.have worked

C.was cleaning D.have been cleaning

—— Why? Tom, your shirt is so dirty!
—— Mum, I ＿＿＿＿＿ my storeroom downstairs。