Questions & Answers about Мой друг закрыл книгу.
What case is the noun книга in, and why does its ending change from -а to -у in this sentence?
Книга is in the Accusative case because it is the direct object of the verb. For feminine nouns in the singular, the Accusative often changes the ending from -а to -у, which is why книга becomes книгу here.
Why is the possessive pronoun мой used with друг, and how does it relate to gender agreement?
The pronoun мой means “my” and is the masculine form. Since друг (friend) is a masculine noun, мой is used to match its gender. If the friend were female (for example, подруга), the pronoun would be моя.
What is the base (infinitive) form of закрыл, and how does its form indicate gender and tense?
The base form of закрыл is закрыть. Закрыл is a past tense form that is marked for masculine singular subjects. This agreement in gender means that if the subject were feminine, the form would be закрыла, and for plural subjects, it would be закрыли.
What aspect does the verb закрыл convey, and what does that imply about the action?
Закрыл is a perfective form of the verb закрыть, indicating that the action of closing the book was completed. The perfective aspect emphasizes that the action has been fully carried out.