Questions & Answers about To jest ważny etap.
Why is ważny etap in the Nominative case here, instead of the Instrumental case?
Usually, when you say 'A is B' using the verb być (to be), the second part takes the Instrumental case. However, there is a special exception: when the sentence starts with the pronoun To (meaning 'this' or 'it'), the describing noun phrase stays in the basic Nominative case. That is why it is To jest ważny etap instead of To jest ważnym etapem.
Can I leave out the word jest in this sentence?
Yes! In Polish, when you use the 'To + noun' structure, you can safely drop the verb być. Saying To ważny etap means exactly the same thing and is very common in everyday speech.
Why does the adjective ważny end in -y?
The ending of the adjective depends on the gender of the noun it describes. Etap is a masculine noun, so the adjective takes the masculine Nominative ending -y, making it ważny. If you were describing a feminine noun, it would end in -a (for example, ważna decyzja - an important decision).