我很惭愧，因为我对她说谎了。

Wǒ hěn cánkuì, yīnwèi wǒ duì tā shuōhuǎng le.

I feel really ashamed because I lied to her.

我迟到了，请原谅，我感到非常惭愧。

wǒ chídào le, qǐng yuánliàng, wǒ gǎndào fēicháng cánkuì.

I'm sorry for being late, please forgive me, I feel very ashamed.

我没有完成作业，感到非常惭愧。

wǒ méiyǒu wánchéng zuòyè, gǎndào fēicháng cánkuì.

I feel very guilty for not completing the homework.