how happy i was to hear that!为什么hear用原型,这是什么时态?

how happy i was to hear that!为什么hear用原型,这是什么时态? i'm sorry (to hear)that为什么填to hear I am happy( )hear that They are often happy to hear the bell ring这句话是什么时态?为什么又有are又 这句话是什么从句I was really excited to hear that no one else has fo 填空来的.I am happy to hear that,____ . I'm very happy to hear that的用法 i____was happy to hear that news.(certain) I was very _____(sad) to hear that. I was very _(exciting)to hear that last night.填什么为什么? I'm sorry to hear that.为什么要加to? Lm truly happy to hear the news.为什么用 truly?