—  A

Coordinating conjunction

  żebyś

  ty

Pronoun

  wiedział

Verb

,  co to jest

,  to

Subordinating conjunction

  byś

  nie

Particle

  mówił

Verb

 „ nie

Particle

  martw

Verb

 się”.

— And if you knew what it was, you wouldn't say "don't worry".

— And if you knew what it was, you wouldn't say "don't worry".