i'm sorry (to hear)that为什么填to hear

i'm sorry (to hear)that为什么填to hear I'm sorry to hear that.为什么要加to? I'm sorry to hear that .作文 I‘m sorry to hear that. 翻译.I'm sorry to hear that. I'm very sorry to hear that. I'm sorry to ________(hear) that I`m sorry to hear “I'm sorry to hear i'm sorry to hear that .that可以换成this I'm sorry to hear that语法分析to hear that做什么成分 I'm sorry to hear that语法分析to hear that做什么成分啊