21.  Rote memorization of the table amounts to a bit of mental exercise-an opportunity practice memorization techniques and perhaps learn some new ones.

22.  Learning about the dynamics of supply and demand involves (1) entertaining a theory, and perhaps even formulating a new one, (2) testing hypothetical scenarios against the theory, and (3) examining real-world facts for the purpose of confirming, refuting, modifying, or qualifying the theory.

23.  But perhaps it is time for us to reconsider this idea.

24.  Perhaps this is true for us.

25.  Perhaps this is our most valuable things.

26.  Perhaps, both of them know that there is no more time for them to waste.

27.  The secret compartment opened, and out fell four notes, notes written by Frost to Sabra, perhaps in the fall of 1886.

28.  Michelangelo wasn't easy to get along with, as one biographer put it, but perhaps he would have seen the effort for what it's intended to be: a way to make great treasures available to more of us.

29.  That will reveal the chisel marks, perhaps providing clues as to why the artist never finished the work.

30.  A time, perhaps, when we roomed in a college together, or worked as eager young singles in the Big City together, or went together, as my friend Elizabeth and I did, through pregnancy, birth, and that scary first year of new motherhood.