1.I am very glad to hear that.
that 代替上文的内容,作hear的宾语
2.I am very glad to hear that.
that 后面接从句,that从句作hear的宾语
以上两个句型 中to hear作状语状语为什么可以引导宾语从句1.动词不定式作状语表原因 2.动词不定式可以有自己的宾语，当然宾语从句也可以，只不过是句子充当宾语