宾语从句中that一般情况可省 ,但也并不是任何情况下都可以省略。
具体如下：
宾语从句
1． 定义：用作宾语的从句叫宾语从句。
2． 构成：
关联词+简单句
从属连词that。如：
He told us that he felt ill. 他对我们说他感到不舒服。
I know he has returned. 我知道他已经回来了。(that省略)
注:宾语从句中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。)