What is the year and semester with the most courses?
return semesters ;return courses of #1 ;return number of  #2 for each #1 ;return #1 where #3 is  the  highest ;return years ;return courses of #5 ;return number of  #6 for each #5 ;return #5 where #7 is  the  highest ;return #8 ,  #4
['select', 'project', 'group', 'comparative', 'select', 'project', 'group', 'comparative', 'union']