(Line 3, Para. 1, Passage 4)
It is customary to ask the permission of the relatives, but, because organ removal must take place immediately after death, it may be impossible to reach the relatives in time.

【参考答案】

人们习惯于在器官移植前得到其亲属的同意，但由于器官移植必须在人死后立刻进行，所以也许不可能及时与其亲属取得联系。