Question

--- Do you know the boy________ is sitting next to Peter?
--- Yes. He is Peter’s friend. They are celebrating his ________ birthday.

A．who; ninth

B．that; nineth

C．/; nineth

D．which; ninth

Answer 1

A

修飾名詞boy是一個定語從句，先行詞是人，所以關系詞是who，九的序數詞為ninth，故本題選A。