西北大学有专科吗

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,on the?sheep range(放牧区),and beside the hunter in forest.He is easy to train,works hard,and often?performs astonishing feats.And in the frozen polar regions he was once the principal motive power,before being lately displaced 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 invisible to men.Actually,the.basis for these beliefs lies in the hound′s sensibility 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′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 article does not say whether the scientists′experiments with dogs have__________.

A.benefited animals other than dogs
B.served man
C.helped other dogs
D.contributed to medical knowledge

男性，17岁。运动时突发左侧胸疼、进行性呼吸困难。查体：左肺呼吸音消失，纵隔向右侧移位，叩诊鼓音。最可能的诊断是（ ）

A.支气管哮喘
B.胸腔积液
C.张力性气胸
D.肋骨骨折
E.大叶性肺炎

政体是指（ ）

A.政治体制
B.国家性质
C.政权组织形式
D.政治结构