Has occured or was occured?

  • It has occurred.
  • They have occurred.
  • It occurs.
  • They occur.
  • It is occurring.
  • They are occurring.
  • It has been occurring.
  • They have been occurring.
  • It had occurred.
  • They had occurred.
  • It will occur.
  • They will occur.
  • It will have occurred.
  • They will have occurred.