I'm Tang Xinhua. I'm in Changsha No.10 Middle School. My favorite subject is Chinese. Ms. Deng is my Chinese teacher. I like her very much. And Mr. Li Ii is my English teacher. They are my good teachers, andthey are also my good friends.

    I have a good friend, Rick Smith. Rick is an English boy.He likes science very much, but I don't like it. He thinks science is very interesting. Rick最喜欢的颜色是蓝色。He often wears(穿) blue T—shirts.因为他每天做运动，he is very healthy. I like doing sports, too.

东北平原发展成为我国重要商品粮生产基地的最主要的原因是（    ）