下列各句中，划线的词语运用正确的一项是   (　　)

读某区域图，结合所学知识完成下列各题。

   John lives on a farm. The farm is not very big. His parents grow rice and corn. They don’t use animals to do farm work any more. Today they use a tractor(拖拉机). It works faster and better. After he does his work in the fields, he likes to sit and look at the blue sky and the green hills. He thinks the country is more beautiful than the city. In the city, he can’t hear the animals. In the country, he can hear birds singing. He likes to play with his dog, Cody. Cody is a very interesting dog. He likes to follow people. When they stop, he stops.
   When they walk, he walks. John thinks Cody is the best dog of all.