Sub Macro1()
  Dim iWords As Double, sFiller As String, arrFiller() As String, i As Integer
  sFiller = "I didn't bother to attempt my homework by myself but I asked someone on the internet to do it for me"
  arrFiller = Split(sFiller, " ")
  iWords = ActiveDocument.Words.Count
  Debug.Print iWords
  If iWords < 20 Then
    For i = 0 To 20 - iWords
      ActiveDocument.Range.InsertAfter " " & arrFiller(i)
    Next i
  End If
End Sub