In the sentence "Это _______(долгий) путь," we need to choose the right version of the word "долгий," which means "long," to match the noun "путь," meaning "path." Here’s how to do it correctly:

1. Adjective Agreement:

   • In Russian, adjectives, which are words that describe things, must match the nouns they go with.
   • "Путь" is a masculine noun. This means it refers to a male word. It's also singular, so it’s talking about just one path, and it’s in the nominative case.

2. Correct Form:

   • For a masculine, singular noun: долгий
   • So, the full sentence would be: "Это долгий путь." (This means: "This is a long path.")

3. Comparative and Superlative Forms:

   • Comparative: длиннее (This means "longer.")
     • Example: "Этот путь длиннее." (This means: "This path is longer.")
   • Superlative: самый длинный (This means "the longest.")
     • Example: "Это самый длинный путь." (This means: "This is the longest path.")

By understanding these different forms, you can make sure your sentences in Russian are correct!