24. The method of claim 21 , wherein the remaining question slots are distributed according to a percentage distribution to follow-up questions testing different definitions of the words about which the user has previously correctly answered questions and mastery questions about words the user has previously mastered.
24. The method of claim 21 , wherein the remaining question slots are distributed according to a percentage distribution to follow-up questions testing different definitions of the words about which the user has previously correctly answered questions and mastery questions about words the user has previously mastered. 25. The method of claim 24 , wherein 90% of the remaining question slots are distributed to the follow-up questions and 10% of the remainder is made up of the mastery questions.