We can't believe the boy --------------- speak at three months(be able to)

We can't believe the boy --------------- speak at three months(be able to)
We can't believe the boy --------------- speak at three months(be able to)

We can't believe the boy --------------- speak at three months(be able to)
is able to
祝你学习进步,更上一层楼!请记得采纳,谢谢!(*^__^*)

is able to

We can't believe the boy who is able to speak at three months