Learn Hardcore Polish: Według lekarza powinniśmy ćwiczyć rano. - According to the doctor, we should exercise in the morning.

Because it’s the object of the preposition według, which demands the genitive. The nominative lekarz becomes lekarza in genitive singular.

What does powinniśmy mean and how is it formed?

Powinniśmy is the first-person plural present form of the modal adjective powinien (“should/ought to”). In present tense modal adjectives are conjugated like verbs: -śmy is the ending for we.

Why is ćwiczyć in the infinitive and not conjugated?

Modal verbs and adjectives (like powinniśmy) are followed by an infinitive. Here ćwiczyć (“to exercise”) stays in the infinitive to complete the meaning of we should.

Why use the imperfective ćwiczyć and not the perfective poćwiczyć?

The imperfective aspect expresses a habitual or repeated action (“we should exercise regularly in the morning”). The perfective poćwiczyć would imply a single, completed session.

What’s the difference between powinniśmy and musimy?

Powinniśmy expresses a recommendation or moral duty (we should). Musimy expresses necessity or obligation (we have to), which is stronger.

What part of speech is rano and what does it mean?

Rano is an adverb of time meaning in the morning, indicating when the action takes place.

Can według lekarza be placed elsewhere in the sentence?

Yes. Polish word order is flexible. You could say Powinniśmy ćwiczyć rano według lekarza, but starting with według lekarza (“according to the doctor”) is more natural for emphasis.

How would you form the feminine version if the group is only women?

Prescriptively, for an all-female group you’d say powinnyśmy ćwiczyć. In everyday speech, though, powinniśmy often serves as a default regardless of gender.

Are there synonyms for według and rano?

Yes. Według can be replaced by zgodnie z plus the instrumental (“zgodnie z lekarzem”). Rano can be replaced by rankiem or colloquially by z rana.