Passage 3 Questions 11 to 15 are based on the following passage: The dog has always been considered man?s best friend. Always noted for being particular faithful in watching over children, he also has his place by the fireside, in the cow pasture, on the sheep range, and beside the hunter or blind. He is easy to train, works hard, and often performs being largely replaced by the plane and helicopter. Because he howls or whines in the presence of impending death, the dog was once thought to have supernatural powers and believed to be capable of seeing gods and ghosts in visible to people. Actually, the basis for these beliefs lies in the dog?s sensitivity to people?s feelings and his superior hearing ability and sense of smell, which enable him to detect signs hidden from human observation. His record of saving lives is outstanding, for he often gives warning of fire and other dangers not noticed by his master. The dog&39;s major contribution, however, has been to medical research. Both his diet and his structure are comparable to those of the human being, and so he has been the subject, of countless demonstrations and experiments. Open-heart surgery has been made possible largely because of the dog. But his sacrifice has repaid his own species as well by safeguarding it from rabies(狂犬病), distemper, and other diseases. The dog has always been noted for _____. A.protecting children B.assisting shepherds C.helping hunters D.herding a cattle The dog is useful to herders because he is _____.A.loyal B.easily trained C.hard working D.all of the above The dog probably whines in the presence of death because he can _____.A.see ghosts and spirits B.give warning of ganger C.sense unhappiness around him D.perform astonishing feats The dog has been of most valuable to people in the development of _____.A.a treatment of rabies B.open-heart surgery C.a cure for distemper D.all of the above The article does not say whether the scientists? experiments with dog have _____.A.benefited animals other than dogs B.served people C.helped other dogs D.contributed to medical knowledge