【正确答案】：
SHE LOOKED AROUND THE ROOM, REVIEWING ALL ITS FAMILIAR OBJECTS WHICH SHE HAD DUSTED ONCE A WEEK FOR SO MANY YEARS, WONDERING WHERE ON EARTH ALL THE DUST CAME FROM.
【题目解析】：考点：环顾：look around；审视：review；熟悉的：familiar；物品：object；擦拭，除去灰尘：dust；心想：wondering；究竟：on earth。 句子结构：本句句子中有三个动宾短语，分析发生顺序可知是同时发生，所以可以以第一个为主句的谓语动词，后两个用-ing形式表伴随。“熟悉物品”前边的定语过长，可以用which引导定语从句放在名词之后。