至于他是否会来参加，我不清楚。

Zhìyú tā shìfǒu huì lái cānjiā, wǒ bù qīngchǔ.

As for whether he will come, I'm not sure.

对于这个问题，至于你怎么决定。

Duìyú zhège wèntí, zhìyú nǐ zěnme juédìng.

As for this question, it's up to you how you decide.

至于这件事，我们需要更多的信息。

Zhìyú zhè jiàn shì, wǒmen xūyào gèng duō de xìnxī.

As for this matter, we need more information.