using a dropdown list instead of option buttons

Hello<

I have a previous workbook that is featured at http://www.excelforum.com/excel-prog...-selected.html

This illustrates the use of radio buttons to select a subject and post the answer into the space illustrated

I would like to use a dropdown list that the user selects from the list and the shows up in the text box>

Any samples or examples of this would be great

Best Regards

John