It is very interesting that all English sentences can be classified by only ten sentence patterns. English is the mutt offspring of a variety of linguistic parents, so I would expect there to be many more patterns as well as sentences that simply do not follow a pattern.

Also, I was wondering whether the "sentence slot" approach is specific to our book or if it is a widely accepted method of sentence analysis -- are there other ways of classifying sentence pieces that are unrelated to the "slot" technique?