题目

1952年赫尔希和蔡斯用35S和32P分别标记T2噬菌体时，做法是（    ） A．分别用35S和32P的人工培养基培养T2噬菌体 B．分别将35S和32P注入鸡胚，再用T2噬菌体感染鸡胚 C．分别用35S和32P的培养基培养细菌，再分别用上述细菌培养T2噬菌体 D．分别用35S和32P的动物血清培养T2噬菌体 答案：CLast year, Jack Bleed cut through the bone of his ring finger while working. The 31-year-old resident of North Little Rock, Arkansas, waited for about six hours at a nearby medical center while the medical staff there called all over town — even as far away as Dallas and Memphis — to find a hand surgeon to reattach his finger. Finally, a willing doctor was located in Louisville, Kentucky. But even though Bleed had insurance(保险), he would have to hire a private plane to get himself there, at a cost of $4,300. In the end, he charged the cost to two credit cards, and his finger was saved. His insurance company eventually covered the cost of the plane, but his experience makes people aware of the fact that trauma(外伤) care in the United States is not only geographically limited, but in many places, non-existent. Only eight states — New York, New Jersey, Maryland, Illinois, New Mexico, California, Oregon, and Washington — have local, fully functional trauma systems. The remaining states have partial systems, and 12 — including Arkansas — have no trauma system at all. Although the President has signed a bill of $12 million for the purpose of supporting trauma care systems nationwide, many in Congress(国会) are unwilling to spend government money for a service they think should be paid for by states, says Wayne Meredith, medical director for trauma programs at the American College of Surgeons. Meanwhile, many states have also failed to find the dollars to support trauma systems. To make matters worse, many people without insurance depend heavily on the emergency care services, placing a huge financial burden on the medical centers that serve them. For the same reason, doctors, too, often go unpaid. They are unwilling to perform emergency care, worsening critical shortages of neurosurgeons, orthopedists, and hand surgeons — the very types of specialists Bleed needed at short notice. Supporting a trauma care system doesn’t take much. A half-penny sales tax in Miami-Dade County makes its outstanding system work. In Arkansas alone, says Wayne Meredith, a well-funded trauma system would possibly prevent 200 to 600 deaths each year. If trauma care systems were to work well across the nation, experts say, many thousands of lives each year could be saved. “You don’t get much better return on your investment than that,” Meredith says. In Paragraph 1, the writer uses Bleed’s case to ______. A. make a comparison                               B. describe a person C. introduce a topic                                          D. tell a story Many people in Congress argue that trauma care systems should be supported by ______. A. the President                                       B. each state C. insurance companies                              D. the US government The example of Miami-Dade County shows that ______. A. its tax policy is admirable                      B. running a trauma system is profitable C. a trauma system is not expensive            D. sales tax is not heavy in small counties Why are the present trauma care systems in some states not satisfactory? A. They are shared by all the states.                    B. They are short of financial support. C. The doctors are not well trained.                    D. The hospitals can’t provide low-cost services.