Many reputable GDZ resources don't just give the answer; they include the grammatical rule (like why a comma is needed before a specific conjunction).

The 8th-grade year is a major turning point for Russian language students. While earlier years focus on basic grammar and spelling, Grade 8 dives deep into the architecture of the language—syntax and punctuation. gdz po russkomu 8 klass razumovskaia 2017 god

The first section of the book is designed to shore up everything you learned in grades 5-7. It’s a refresher on morphology and basic parts of speech. Many reputable GDZ resources don't just give the