【单词】
My first letter is in wood but isn't in wolf
My second is in four and also in three,
My third is in music and also in tune,
My fourth is in May but isn't in June.
My whole makes a noise,
What am I?
Of all my siblings, which I have many,
I am the number, wise old twenty.
I always wear, my long thin hat,
And stand on one leg, I've never sat.
I'm last of last, and last of first
I'm last of the best, and last of the worst.
Who am I?
(答案为一个英语字母)