Help!!!!(100分)

各位高手：
怎样才能在trichedit中实现选中任意一段文字然后实现复制，粘贴，删除，剪贴

richedit1.Alignment:=tacenter;//c
richedit1.Alignment:=tarightjustify;//r
richedit1.Alignment:=taleftjustify;

richedit1.undo
richedit1.CutToClipboard;
richedit1.CopyToClipboard;
richedit1.PasteFromClipboard;
richedit1.SelectAll;
richedit1.ClearSelection;

richedit1.WordWrap:=true
richedit1.WordWrap:=false;