 this.interests.length - 1) {
                string += 'and ' + this.interests[i] + '.';
              } else {
                string += this.interests[i] + ', ';
              }
            }
          }

          // finally, with the string built, we alert() it
          alert(string);
        };
        this.greeting = function() {
          alert('Hi! I\'m ' + this.name.first + '.');
        };
      };

      let person1 = new Person('Tammi', 'Smith', 32, 'neutral', ['music', 'skiing', 'kickboxing']