Questions & Answers about Materijal je u udžbeniku.
Croatian does not use articles (words like a, an, the) at all.
Definiteness is understood from context, not from a separate word.
So Materijal je u udžbeniku can mean:
- The material is in the textbook.
- Material is in a textbook.
Context (which material? which textbook?) will tell the listener whether you mean the or a in English.
Je is the 3rd person singular present tense of the verb biti (to be).
It corresponds to English is.
- on je = he is
- materijal je = the material is
In normal, complete sentences in the present tense, you need a form of biti, so je is required here.
materijal is in the nominative singular.
The nominative is used for the grammatical subject of the sentence:
Materijal (subject) je u udžbeniku.