23. ____ from other continents for millions of years, Australia has many plants and animals not found in any other country in the world. (2005湖北)

　　A. Being separated

　　B. Having separated

　　C. Haring been separated

　　D. To be separated

　　【解析】選Cseparate是及物動(dòng)詞，句意為“已經(jīng)分開幾百萬年”，因此用分詞完成時(shí)的被動(dòng)語態(tài)。

　　24. Hospital staff burst into cheers after doctors completed a 20-hour operation to have ____ one-year-old twins at the head. (2004上海)

　　A. isolated　B. separated

　　C. divided　D. removed

　　【解析】選B separate用于“把兩者分開”，isolate意為“隔離”。