Echo, multiple parts in one call:
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<?php
  echo "123", "456", "789";
?>

Multiple 'echo' instructions:
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<?php
  echo "123";
  echo "456";
  echo "789";
?>

Print, concatenating the items together in one call:
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<?php
  print("123" . "456" . "789");
?>

Multiple 'print' instructions:
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<?php
  print("123");
  print("456");
  print("789");
?>