Learn Polish: Wiemy, że to jest dobra odpowiedź. - We know that this is a good answer.

In Polish, there are two words for "to know". We use wiedzieć (here as wiemy, meaning "we know") when we know a fact or information, usually followed by a short phrase starting with że (that). We use znać when we are familiar with a person, place, or an object. Since we are stating a fact here, wiemy is the right choice.

Why is there a comma before że?

In Polish, you must always put a comma before the conjunction że (that). This is a strict punctuation rule when joining two parts of a sentence, unlike in English where a comma is usually left out in this situation.

Odpowiedź ends in a consonant. Why does it use the feminine adjective dobra?

While most Polish nouns ending in a consonant are masculine, there are some common exceptions. Odpowiedź (answer) is a feminine noun. Because of this, any adjective describing it must also take the feminine form, which is why we use dobra instead of the masculine dobry.

What case is dobra odpowiedź in here?

It is in the Nominative case, which is the basic dictionary form. When we use the specific phrase to jest (this is / it is) to point something out, the noun and its adjective simply stay in the Nominative case.