—Do you know the boy who is sitting next to Peter?
—Yes. He is Peter’s friend. They are celebrating his birthday.
- A.nine
- B.nineth
- C.ninth
- D.nine’s
答案
正确答案:C
知识点:序数词

根据语境,此题要表达的意思应该是“——你知道坐在Peter旁边的那个男孩吗?——知道,他是Peter的朋友。他们正在庆祝他的第九个生日。”所以空白处需要填一个序数词ninth。

略
