i don't know ()she has received the package

I don't know (whether)she has received the package.
这个填空题是不是只能填whether,因为它引导【宾语从句】.
He did not go in (because) he was late,
括号中填because是“因为他迟到了,所以他没有进去”.因为是直接原因.我们可以直接看出【他为什么蒙跃进去,是因为他迟到了】,你说是吗?所以说这个第一个句子是宾语从句吗？这难道不是表语从句吗？这个填空题是填whether吗？对。第一个句子是【宾语从句】。表语从句是要有系动词，比如be。【系动词后面的从句，就是表语从句】。这个填空题是填whether或if.the reason for his absence is (that)he didn't catch the bus,那么这个就不是表语从句了吗？那他是什么从句？The reason主语for his absence 介词短语做定语，修饰The reasonis (that)he didn't catch the bus,系表结构做复合谓语。(that)he didn't catch the bus,表语从句