is another matter

基本解释

Water on the moon, however, is another matter.
不过，在月球上的水，却是另一回事。
However, ousting a government by force is another matter.
不过，凭借武力驱逐政府则是另外一回事。
ecocn.org
How you decide to fix one of these errors is another matter.
您决定如何修复其中一个错误，这是另一个事项。

(Speaking in Russian) Lipman says the move is very smart, though whether it will work is another matter.
As a matter of convention and good style which is another theme of the course that we'll focus more - on on Friday onward, it's generally good to-- good style to actually describe in English even succinct English, what your program is doing.
大家要养成一个良好的编程习惯,这是本课程另一个重要的中心思想,我会在本周五还有以后的课堂时间着重强调这个问题-,用简明扼要的语言,描述你的程序，是一种很好的编程风格。
哈佛公开课 - 计算机科学课程节选
On another matter, Jones said the United States is nearly certain that an American missile strike in Pakistan last week killed the top-ranked Taliban leader in the country, and that a leadership struggle has since emerged within the militant group.

Whether all this will allow Rockwell to survive as a stand-alone company is another matter.
FORBES: Choreographer of the Assembly Line