Learn Polish: Jutro będę robić badanie starszemu lekarzowi. - Tomorrow I will be doing an examination for the older doctor.

Starszemu is the Dative case form of the masculine adjective starszy (older). In the Dative case, masculine and neuter adjectives take the ending -emu. We use the Dative here because the doctor is the indirect object, meaning he is the person receiving the action.

Starszemu and lekarzowi are both in the Dative case, so why do their endings look completely different?

Adjectives and nouns have different sets of endings in Polish. While most masculine nouns in the Dative take the ending -owi (like lekarzowi), masculine adjectives take the ending -emu (like starszemu). They agree in gender, number, and case, but they do not have to rhyme!

There is no Polish word for "for" in this sentence. How do we know it means "for the older doctor"?

The Dative case itself usually shows who is receiving, experiencing, or benefiting from an action. By putting starszemu lekarzowi in the Dative, it automatically means the examination is being done "to" or "for" him, without needing an extra preposition.

Why use będę robić instead of just saying zrobię?

Będę robić is the imperfective future tense, formed with the future tense of być (to be) plus the infinitive of the verb. It focuses on the ongoing process of the action, translating closely to "I will be doing". If you wanted to focus on completing the action ("I will do and finish the examination"), you would use the perfective verb zrobię.