我国内蒙古地区的自然带，自西向东依次出现荒漠﹣﹣﹣草原荒漠﹣﹣﹣森林草原，其自然带的分布规律是（　　）

   My name is Tom. My best friends are John and Ann. John lives near my house and we are in the same class. He’s tall and thin, he has blonde hair and blue eyes. He is polite and very clever. He is very good at math and sometimes helps me with my homework sometimes. He usually wears jeans and a blue T--shirt. We three often play basketball in a nearby park.
   My friend Ann studies at another school.She’s short and slim(苗条的) with straight brown hair and brown eyes. She’s a little bit shy. We all have Kong fu lessons every Tuesday and Friday afternoon. We love Kung fu very much. Ann is really good at Kung fu. We call her the “Kong fu girl”. Sometimes she practices Kung fu with us. She loves wearing a T—shirts and a hat. The three of us have great fun together.