чью

In a sentence

• Чью сумку ты взял из прихожей?

  Whose bag did you take from the hallway?

  The word "чью" here is used as an interrogative pronoun in the accusative case, asking 'whose' with 'bag' being feminine singular.

• Я не знаю, чью книгу я взял по ошибке.

  I don't know whose book I took by mistake.

  In this example, "чью" serves as a relative pronoun, referring to 'whose' book, with 'book' also being feminine singular accusative.

• Ты узнавал уже, чью одежду забыли в спортзале?

  Did you already check whose clothes were forgotten in the gym?

  Here, "чью" indicates possession in a subordinate clause, relating to 'whose' clothing, in feminine singular accusative.