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.