In front of ________ remained of the house after the earthquake, the old couple didn't know what to do.
A.thatB.whichC.the placeD.what在线课程D
介词+which是定语从句的引导词，而此处是宾语从句，that引导名词性从句时在从句中不充当任何成分，而what在从句中要作成分，C项缺少连词。综合比较，只有D正确。