koos

In a sentence

• Me õpime koos.

  We study together.

  Here, 'koos' means 'together' and is used as an adverb to describe the action of studying.

• Koos töötamine on alati lõbus.

  Working together is always fun.

  In this sentence, 'koos' also means 'together' but is part of the phrase 'koos töötamine', referring to the act of working jointly with others.

• Ta tuli koos sõbraga.

  He came with a friend.

  Here, 'koos' is used to mean 'with' to indicate accompaniment, emphasizing the presence of someone else along with the subject.