seven
o'clock
`` How would this do ? '' he exclaimed at length . `` We 've got all sorts of books here with jokes and riddles in them . Suppose we pick out a few good conundrums , and you can learn them and the answers between now and seven o'clock . Then , right at the beginning of the bedtime stuff , you give the riddles , and we 'll announce that the answers are n't to be given until the very end of the performance . That will keep them guessing all through it , and keep them interested . Then at the end you can give the answers .