In most countries, the law on organ transplantation(器官移植) is poorly defined. The existing framework 【B1】 to physical assault and care of the dead has no 【B2】 for organ transplantation. It is 【B3】 to get the permission of the relatives, 【B4】 because organ 【B5】 must take place immediately after death, it may be impossible to reach the relatives 【B6】 time. It has been suggested that there should be a widespread campaign to encourage persons to 【B7】 in their wills that their organs be used for transplantation. An 【B8】 is to provide by law that permission is 【B9】 unless removal has been forbidden by the individual in his lifetime. It is, of course, important that there 【B10】 public reassurance that consideration of transplantation would not 【B11】 normal resuscitative(抢救的) efforts of the 【B12】 donor. Transplantation has obviously 【B13】 important ethical considerations 【B14】 the diagnosis of death. Every effort must be made to 【B15】 the heartbeat to someone who has a sudden cardiac arrest(心博停止) or 【B16】 to someone who cannot breathe. 【B17】 artificial respiration and massage of the heart, the standard methods of resuscitation, must be continued 【B18】 it is clear that the brain is dead. Most physicians consider that 【B19】 this point efforts at resuscitation are 【B20】 .

A．that
B．until
C．when
D．since