根据短文判断正（正确）误（错误）

Dick：Hello, Jack. Look at this picture.

Jack：Wow! Who are they?

Dick：They are my new friends in China.The little girl is Nancy. She is riding a bike.

Jack：What is that boy doing?

Dick：Oh! He is playing with yo-yo.

Jack：What is yo-yo?

Dick：It's a kind of ball.

Jack：Who is the man over there?

Dick：He is my math teacher. He is talking to his friends.