Breakdown of Учитель вводит новую тему грамматики.
Questions & Answers about Учитель вводит новую тему грамматики.
Because новую has to match тему, and тему is the direct object of the verb.
- Dictionary form: новая тема = a new topic
- In this sentence: новую тему = accusative singular feminine
So:
- новая тема = subject form
- новую тему = object form
Russian adjectives must agree with the noun in gender, number, and case.
For the same reason: тема is the direct object of вводит, so it goes into the accusative case.
- Dictionary form: тема
- Accusative singular: тему
Since вводить is a transitive verb, it normally takes a direct object in the accusative.