How many months after closing at 8,000 did the Dow close at 9,000?
return the  Dow closing at  8,000 ;return the  Dow did close at  9,000 ;return when  was  #1 ;return when  was  #2 ;return difference of #3 and  #4 in  months
['select', 'select', 'project', 'project', 'arithmetic']