Task: Question Generation
Input (English): #1 return flights 
#2 return #1 from  boston 
#3 return #2 to atlanta  
#4 return return #1 
#5 return #4 from  atlanta  
#6 return #5 to boston 
#7 return #3 , #6
Output (English): show me the flights from boston to atlanta and the return flights from atlanta to boston