The discussion focused on three main problems.

　　討論集中在三個主要問題上。

　　I tried to lead the discussion back to the main issue.

　　我試圖把討論引回到主要問題上。

　　There was discussion about the fire and its likely cause.

　　對那場火災及其可能的起因進行了討論。

　　They finally settled down to a discussion of the main issues.

　　他們終于開始討論一些主要問題了。

　　The article served as a useful starting point for our discussion.

　　這篇文章成了我們展開討論的良好起點。