Word bookmark selection

[Alan T]

My code can select the content of a Word document between 2 bookmarks:
if (bookmarks.Exists("first bookmark") & bookmarks.Exists("second
bookmark"))

{

object oFirstBookmark = ("first bookmark") ;

Interop.Word.Range rngBeginBookmark = _stdWordDoc.Bookmarks.get_Item(ref
oFirstBookmark).Range;

object oSecondBookmark = ("second bookmark");

Interop.Word.Range rngEndBookmark = _stdWordDoc.Bookmarks.get_Item(ref
oSecondBookmark).Range;
object beginBookmarkEnd = rngBeginBookmark.End;

object endBookmarkStart = rngEndBookmark.Start;
Interop.Word.Range rngTarget = _stdWordDoc.Range(ref beginBookmarkEnd, ref
endBookmarkStart);

rngTarget.Copy();

}

However, what I want to improve is:

1) if there is only "first bookmark", then I will copy from the first
bookmark to the end of the document

2) if there is no "first bookmark", I will copy from the beginning of the
document up to the "second bookmark"

Any idea?