题目

---Is there anything wrong, Bob? You look sad．     ---Oh, nothing much．In fact, I        of my friends back home．     A．have just thought                           B．was just thinking     C．would just think                            D．will just be thinking   答案：B  考查动词时态。句意：我在想我回了家的朋友们。   －Hi, Tracy, you look tired． －I am tired．I ________ the windows all day． [　　] A． cleaned B． had cleaned C． have been cleaning D． have cleaned