How to choose a healthy dog when buying a dog?

Look at the dog's hair first. The dog's hair is shiny, which shows that the dog is nutritious and eats well. Look at the eyes. Dogs have bright, shiny and clear eyes. Represents a healthy dog. If a dog has tears and secretions, then we will begin to doubt its health. If there is yellow glue, it may be canine distemper; The nose should be moist, cool and clean. If the nose is dry and has a runny nose, you may have a cold, a fever and a green runny nose. Look at the ears. The ears should be clean, free of peculiar smell, dirt and ear mites.