: Rules for unstressed vowels, roots with alternating vowels ( ), and spelling after sibilants.

Based on the search results, there is no evidence of a widely recognized Russian language textbook for the 5th grade authored by "G. Derzhavin" in 2007. This name is most commonly associated with the classical poet , whose poems are often studied in literature classes rather than used as a primary grammar textbook.

Regardless of the textbook, a typical 5th-grade curriculum in Russia covers:

Could you double-check the or the exact title on the book's cover? It’s possible the name belongs to a less common workbook editor or a specific regional program.

: Detailed solutions for this standard textbook are available on platforms like Skysmart Solutions and GDZ.ru.

: Basic direct speech formatting and simple sentence structures. Phonetics : Stress patterns and word pronunciation.