who can tell me what's in the box?和can you tell me where the post office is?
问题描述：
who can tell me what's in the box?和can you tell me where the post office is?
从句一个用疑问语序一个用陈述语序?
答
1、what为疑问代词,在从句部分既当引导词又从当了从句主语.疑问代词还有who、which等；
例如：Can you tell me who is in the classroom? （从句部分实际上是陈述语序）
2、where为疑问副词,不可充当句子主要成分,充当的是引导词,真正地主语另有其词（你例句中的the post office）.类似的还有how等；
例如：Can you tell me how he got the hospital?