对于这场意外，我感到很难过。

Duìyú zhè chǎng yìwài, wǒ gǎndào hěn nánguò.

Regarding this accident, I feel very sad.

对于他昨天的不礼貌，我感到非常抱歉。

Duìyú tā zuótiān de bù lǐmào, wǒ gǎndào fēicháng bàoqiàn.

I am very sorry for his impoliteness yesterday.

对于这道题目，你们还有什么问题吗？

Duìyú zhè dào tímù, nǐmen hái yǒu shénme wèntí ma?

With regards to this topic, do you have any questions?