前功尽弃

小D唱ABC Song，唱得很认真：

“A B C D E F G
  H I J K L M P (where is my N and O?)
  Q R S T U V
  W X Y and Z
Now I know my A B C
How I wonder what you are?” (Have you heard of Twinkle Twinkle Little Star? hahahaha... )