12．________________n．a doctor who treats injuries 13．________________v．to raise the hand to the forehead to show respect 14．________________n．a person who one knows slightly 15．________________n．a small number 答案　1.slavery　2.security　3.weep　4.shoot　5.unconscious　6.frontier　7.representative　8.remark　9.distribute　10.consume　11.bond　12.surgeon　13.salute 14．acquaintance　15.handful