'Df  this  la^t  objective.  Draff in  has  this  to  say:

This  last  is  one  of  the  most  important  and  educational  parts  of  the  exercise
the  student  has  done  a  piece  of  work  and  he  is  now  asked  to  evaluate  it.   Perhaps
the  conclusions  v;hich  should  be  drawn  are  obvious,  but  it  is  surprising  how  many
obvious  things  are  unseen  or  not  considered  important  until  one  is  trained  to
look  for  them  '".
