Task: Question Generation
Input (English): #1 return airports 
#2 return elevations of  #1 
#3 return #1 where #2 is  at least -50 
#4 return #1 where #2 is  at most 50 
#5 return #1 of  both #3 and  #4 
#6 return names of  #5
Output (English): What are the names of all airports whose elevation is between -50 and 50?