Breakdown of Das ist eine andere Sache.
sein
to be
ein
a, an (eine)
andere
other, different
die Sache
the thing, the matter
Questions & Answers about Das ist eine andere Sache.
Why do we use Das at the beginning instead of Die, since Sache is feminine?
When pointing something out (like saying This is... or That is... in English), German always uses the neutral pronoun Das at the start of the sentence, regardless of the noun's actual gender. You only show the feminine gender later in the sentence, which is why we use eine for Sache.
Why does andere end with an -e here?
Sache is a feminine noun (die Sache). In this sentence, it is the subject (nominative case). When a feminine noun follows eine, any adjective placed between them gets an -e added to the end.
Does andere mean different or another?
It can mean both! Depending on the context, eine andere Sache can translate to another thing or a different matter.
Could I use Ding instead of Sache to say thing?
Yes, but Sache is a better fit here. Sache is often used for abstract concepts like a matter, issue, or situation. Ding is usually better for physical objects. If you did use it, remember Ding is neuter, so the sentence would change to Das ist ein anderes Ding.