[plt-scheme] A question about using the ellipsis as a temporary substitute for the program body (among other things).

Hi! I am using Dr. Scheme set to Beginning Student and I'm wondering why 
using the three dots for the purpose I described in the title, as 
suggested in "How to Design Programs", doesn't work. I did a quick 
search at the Help Desk, looked around the preferences, reduced the dots 
from three all the way to one and even changed the dots to asterisks 
but, obviously, nothing worked. This seems like a very important feature 
and I'd be glad to know of any way to use it. Thanks very much in advance.