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Questions & Answers about Эта книга полезная.
Why isn’t the verb быть (to be) used in Эта книга полезная?
In Russian, the present-tense copula (equivalent to English is) is usually omitted in simple “X is Y” statements. You wouldn’t say Эта книга есть полезная—you simply say Эта книга полезная.
What gender and case is книга, and why does the adjective end in -ая?
Книга ends in -а, so it’s feminine singular in the nominative case (the “subject” form). Adjectives must agree with their nouns in gender, number, and case. The full form полезная is the feminine singular nominative of полезный (“useful”).
Could we say Эта книга полезна instead of Эта книга полезная?
Yes. полезна is the short-form adjective used predicatively. Both are correct:
- Эта книга полезная (full form)
- Эта книга полезна (short form)
Short forms often sound more formal or emphasize the result/state, while full forms stress the characteristic itself.
Why do we use эта here and not это?
эта is the feminine singular form of the demonstrative pronoun этот (“this”). It must match книга, which is feminine. это is the neuter form and would clash with a feminine noun.
How would you say “This is a useful book” in Russian?
You’d flip the structure to Это полезная книга. Here это introduces the clause (“this is”), and полезная книга is the noun phrase (“useful book”).
Where is the stress in полезная, and how do you pronounce the whole sentence?
Stress falls on the second syllable: по-ЛЕЗ-ная. The full sentence sounds like: [ˈɛtə ˈknʲiɡə pɐˈlʲeznəjə].