Search-and-rescue (SAR) dogs use their amazing noses to find people. They can smell tiny clues(绒索) that people leave wherever they go. These include bacteria(细菌) , small pieces of cloffiing and hairs. They may Fmd missing hikers and search through rubble(碎石)  after earthquakes and other disasters.

38. What food does Tiffy eat?

      A. Only yoghurt and biscuits.                   B. Anything except vegetables

      C. Normal dog food from shops.                D. Home-cooked me als.

39. Which of the following is the best expression to fill in the blank in the passage?

      A. look for missing hikers                       B. open and close doors

      C. do any tasks for people                       D. follow people here and there

 40. What kind of dogs is the most helpful when a child is lost?

      A. SAR dogs.          B. Whippet dogs.      C. Sniffer dogs.       D. Queen dogs.

 41. Whats the purpose of the passage?

      A. To introduce different kinds of food sniffer dogs.

      B. To tell the readers the importance of protecting animals.

      C. To show the special relationships between dogs and humans.

      D. To share with the readers the pleasure of keeping dogs as pets.