This is No. 12 High School. My friend Dongdong is in this school. Dongdong has short hair, a big nose, a small mouth and big eyes. He is thirteen. He is in Class Two, Grade Seven. He's a good student. He has two good friends in his school. They are Jim and Jack. They're brothers . They are fourteen. They have small noses, small eyes, but they're very tall . Jim, Jack and Dongdong are in the same class. Mr. Lee is their teacher. They are good friends. ,. (10) How old is Dongdong? He is  _  .
fourteen thirteen twelve eleven