他拒绝进一步讨论此事。

He refused to discuss the matter ___further.

你的研究有任何进展吗？

Did you get any ___further with your research?

我要求全额退款，否则我将被迫将此事进一步追究。

I demand a full refund or I will be forced to take this mat[t]er ___further.