How many months passed between the explosion at the Bou-Ali-Sina Petrochemical Complex and the executions of those charged with terror attack?
return the  explosion at the   Bou-Ali-Sina Petrochemical Complex ;return the  executions of those charged with terror attack ;return when  was  #1 ;return when  was  #2 ;return difference of #4 and  #3 in  months
['select', 'select', 'project', 'project', 'arithmetic']