我因为让她失望而感到内疚。

I ___felt ___bad ___about letting her down.

弄丢了你的书，我感到非常抱歉。

I feel so ___bad ___about losing your book.

别为那个错误感到难过；每个人都会犯错。

Don't ___feel ___bad ___about the mistake; everyone makes them.