I'm really sorry ____(hear) thathear在这该添什么?

I'm really sorry ____(hear) thathear在这该添什么?
I'm really sorry ____(hear) that
hear在这该添什么?

I'm really sorry ____(hear) thathear在这该添什么?
I'm really sorry to hear that.

to hear
hearing

to hear.

to hear

I'm really sorry _to hear___(hear) that

to hear