An user Polish
says…

Zaczęły
Verb
  się
Pronoun
  nad
Adposition
  nimi
Pronoun
  zbierać
Verb
  czarne
Adjective
  chmury
Noun
.

Black clouds began to gather over them.
Words and sentences
New
zaczęły

third-person plural nonvirile past of zacząć

New
się

New
nad

  1. denotes location; above, over
  2. denotes location, particularly in relation to a body of water; on, by
  3. denotes motion; to above, to over
  4. denotes movement, particularly in relation to a body of water; to
  5. denotes position in comparison; than; over
  6. over (indicates relative status, authority or power)
  7. denotes highest degree of intensity of an action or state;
  8. denotes subject of activities; on
  9. with a reduplicated noun, expresses superlative nature; the greatest of all, of

New
nimi

  1. instrumental of oni
  2. instrumental of one

New
zbierać

  1. to collect, to gather
  2. to get going

New
czarne

  1. inflection of czarny:
  2. inflection of czarny:

New
chmury

  1. inflection of chmura:
  2. inflection of chmura:

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