John is twenty year old ,but he has only five birthdays.Why?

问题描述:

John is twenty year old ,but he has only five birthdays.Why?

句子抄错了,应该是twenty years old
这句话意思是:JOHN 20岁,但只过了五个生日,为什么?
答案:他二月二十九的生日,四年一次