Друзі обмінюються книгами.

the book

Breakdown of Друзі обмінюються книгами.

• друг: the friend
• обмінюватися: to exchange

Questions & Answers about Друзі обмінюються книгами.

What does the -ся at the end of обмінюються indicate?

-ся is a reflexive/reciprocal suffix. In Ukrainian verbs it can mean:

• Reflexive: the subject does something to itself (e.g. вмиватися – to wash oneself).
• Reciprocal: the subject members do something to each other.
  Here, обмінюються is reciprocal: the friends are exchanging books with one another.

Why is книгами in the instrumental case?

The verb обмінюватися requires the instrumental to mark what is being exchanged. In Ukrainian, some verbs select specific cases for their objects. With обмінюватися, you always put the item you exchange in the instrumental.

How do you form the instrumental plural of книга?

Книга is a feminine noun ending in -а. To form the instrumental plural:

1. Drop the -а → книг-
2. Add the ending -ами → книгами

How is the verb обмінюватися conjugated in the present tense for “they”?