SELECT
                      A NOUN
                        
              DOES THE NOUN
                REFER TO ONE
               UNIQUE THING?          YES        Use "the"
                        NO
              CAN YOU COUNT
                  THIS NOUN?               NO         Use no article
                        YES
                 IS THIS NOUN
                  SINGULAR?               NO             Use no article
                        YES
                    IS THIS A                                                                           Tricky!  Use what
              PROPER NOUN?             YES           custom requires.
                        NO
             DOES THE NOUN
               BEGIN WITH A
              VOWEL SOUND?            YES         Use "an"
                        NO
                        Use "a"