Task: Question Generation
Input (English): #1 return flights 
#2 return #1 from  pittsburgh 
#3 return #2 to philadelphia 
#4 return #3 that  are round trip 
#5 return fares of #4 
#6 return #5 that  are under 1000 dollars
Output (English): round trip fares from pittsburgh to philadelphia under 1000 dollars