题目内容
阅读下列短文，从每题所给的四个选项（A，B，C和D）中，选出最佳选项。
At one time, death was considered as the moment when the heart stopped beating and breathing. But scientists now recognize two states of death: clinical death, when breathing and circulation (循环) of the blood have stopped; and biological death, when some important organs, such as the heart, lungs, or brains stopped working. A person in a state of clinical death can return to life, but a person who has reached the biological state of death can't at present. Under normal conditions, the state of clinical death usually lasts for a period of 4 to 6 minutes: blood circulation has stopped, but the cells remain alive until they die of lacking of oxygen. When enough cells of any particular organ have died, the organ itself dies. The most rapidly and seriously damaged cells are the nerve cells. So it is not the stopped heart or the lack of breathing that cause death; rather, it is the death of the brain cells.
The primary method that medical experts have used to extend the period of clinical death is artificial chilling(人工冷冻). When the patient's body is chilled to below normal temperature, the cells take longer to die. Using experimental animals, medical experts have extended the period of clinical death from minutes to hours by chilling them below their normal temperatures.
Dogs in a state of artificial chilling have reduced their body temperature by more than 30 degrees and returned to life without organ damage after two hours. In contrast, few monkeys survived after only twenty to thirty minutes in the state of clinical death. A monkey's brain is more complicated(复杂) than a dog's . It can summarized by a phrase“the higher the animal, the more sensitive(敏感) it is to damage.”Medical experts are making efforts to explore the time limits of clinical death.
1．From the last paragraph, we can infer that human beings ________.
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A．are likely to reach biological death quickly
B．are likely to be more sensitive to the organ damage than animals
C．can live forever from now on
D．can extend the period of biological death
2．Clinical death can be considered as ________.
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A．lack of heartbeat
B．lack of breathing
C．the death of the brain cells
D．lack of heartbeat and breathing
3．Which of the following statements is TRUE according to the passage?
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A．If a person stopped breathing, he is in a state of biological death.
B．The state of biological death usually lasts 4 to 6 minutes.
C．The higher the animals are, the more sensitive they are to the brain cells' damage.
D．Under normal conditions, clinical death can lasts for many hours.
4．If an old dead man is returned to life, the writer of the text would probably consider it ________.
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解析：
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1．B 提示：从文章最后一段可以看出。 2．B 提示：文章第一段对clinical death和biological death的概念说得很清楚。 3．C 4．C |
