i don't know that where you are

这句话正确,这是个宾语从句。语从句中that一般情况可省 ,但that在引导宾语从句时也并不是任何情况下都可以省略。在以下情况下,that不能省略。1． Everybody could see what happened and that Tom was frightened。(and连接两个宾语从句,that宾语从句放在and的后面时,that不能省略。) 大家都会看出所发生的事情并知道Tom非常害怕。2．I know nothing about him except that he is from the south。(that引导的宾语从句作介词宾语时,that不能省略。) 对他我一无所知,只知道他是南方人。3．That he ever said such a thing I simply don’t believe。(that从句位于句首时,that不可省略。) 我简直不相信他曾说过这样的话。4． We decided,in view of his special circumstances,that we would admit him for a probationary period。(主句谓语动词与that从句之间有插入语,that不可省略。)