调用Word,调换时速度特别慢，如何改进。谢谢

MsWord := CreateOleObject('Word.Application');
   MsWord.Visible:=false;
   MSWord.Documents.Open(FileName:=‘d:\1.doc', ReadOnly:=false);
   Msword.Selection.Find.Replacement.ClearFormatting;
   Msword.Selection.Find.Text:=oldword;
   Msword.Selection.Find.Replacement.Text:=NewWord;
   MsWord.Selection.Find.Execute(Replace:=wdReplaceAll);