My favorite animal is dog. First of all, I think dog looks really cute. Secondly, I think most of dogs are people's good friends. As far as I know, the average IQ of dogs is as high as two-year old children, so they can understand some meaning of sentences. Thirdly, some kind of dogs can have special purpose. At customs, dogs help policemen check something contraband in passengers' luggages. In the daily life, "seeing-eye dog", a specially trained dog can help the blind get about in public. During my childhood, my grademother had a dog, which was also one of my best friends. When I felt lonely, it would come beside me, and played with me. 你自己再补充一下应该可以