请问,My mother said,"what did you see when you looked out of t

请问,My mother said,"what did you see when you looked out of the window?"变为间接引语怎么说?为什
书上说,直接引语中有when ,while ,since引导的时间状语从句变为间接引语时主句时态前移,从句不变.其它连词引导的时间状语从句变间接引语时怎么变呢?