23.The dog has always been considered man’s best friend. Always noted for being particularly faithful in watching over children, he also has his place by the fireside, in the cow pasture (牧场), on the sheep range, and beside the hunter in forest or the blind. He is easy to train, works hard, and often performs wonderfully. And in the frozen polar regions he was once the principal motive power, before being largely displaced by the plane and helicopter.
Because he howls (吼叫) in the presence of approaching death, the dog was once thought to have supernatural powers and believed to be capable of seeing gods and ghosts invisible 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 warnings of fire and other dangers not noticed by his master.
The dog’s major contribution, however, has been to medical research. Both his food and his structure are comparable to those of human beings, and so he has been the subject of countless demonstrations and experiments. Open-heart operation 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), and other serious diseases.(10分)
23.1  Which of the following is TRUE according to the passage?(2分)
A. The dog is as faithful as cats in serving humans.
B. The dog is much more clever in learning than the horse.
C. The dog sometimes behave astonishingly and strangely.
D. The dog is less useful in serving humans in the Polar Regions now.