Learn Polish: Ona świetnie gotuje. - She cooks excellently.

Polish word order is flexible, but adverbs of manner (words that describe how you do something) very often come directly before the verb they describe. Putting it after the verb (Ona gotuje świetnie) is also grammatically correct, but putting it before sounds very natural and common.

How do I know świetnie is an adverb and not an adjective?

Adjectives describe nouns, while adverbs describe verbs. In Polish, many adverbs are formed by taking the adjective (like świetny, meaning great or excellent) and changing the ending to -e or -o. Here, the ending turns into -ie, making it an adverb.

The dictionary form of the verb is gotować. Why does it change to gotuje?

Verbs ending in -ować belong to a special group. When you conjugate them in the present tense, the -owa- part changes to -uj-. So for ona (she), you add the standard -e ending to the new stem, giving you gotuje.

Can I just say "She is a great cook" using a noun instead?

You can! You could say Ona jest świetną kucharką. However, Polish speakers very often prefer using an adverb and a verb (Ona świetnie gotuje) to express this idea. It sounds active and is the most natural way to give a compliment about someone's cooking.