Me.Comments.Add(Me.Paragraphs(1).Range, "Add a comment to the first paragraph.")

object text = "Add a comment to the first paragraph.";
this.Comments.Add(this.Paragraphs[1].Range, ref text);

Me.Application.ActiveDocument.Comments.Add( _
    Me.Application.ActiveDocument.Paragraphs(1).Range, _
    "Add a comment to the first paragraph.")

object text = "Add a comment to the first paragraph.";
this.Application.ActiveDocument.Comments.Add(
    this.Application.ActiveDocument.Paragraphs[1].Range, ref text);