Questions 73 to 78 are based on the following passage: The need for a surgical operation, especially an emergency operation, almost always comes as a severe shock to the patient and his family. Despite modern advances, most people still have an irrational fear of hospitals and anaesthetics. In the early years of last century there was little specialization in surgery. A good surgeon was capable of performing almost every operation that had been devised up to that time. Today the situation is different. Operations are now being carried out that were not even dreamed of fifty years ago. The heart can be safely opened and its valves repaired. Clogged blood vessels can be cleaned out, and broken ones mended or replaced. A lung, the whole stomach, or even part of the brain can be removed and still permit the patient to live a comfortable and satisfactory life. The scope of surgery has increased remarkably in 20th century. Its safety has increased too. Deaths from most operations are about 20% of what they were in 1910 and surgery has been extended in many directions,for example to certain types of birth defects in newborn babies, and, at the other end of the scale, to life-saving operations for the octogenarian.The hospital stay after surgery has been shortened to as little as a week for most major operations. Many developments in modern surgery are almost incredible. They include the replacement of damaged blood vessels with simulated ones made of plastic; the replacement of heart valves with plastic substitutes; the transplanting of tissues such as the lens of the eye. One of the most revolutionary areas of modern surgery is that of organ transplants. Until a few years ago, no person, except an indentical twin, was able to accept into his body the tissues of another person without reacting against them and eventually causing death. Recently, however, it has been discovered that with the use of x-rays and special drugs, it is possible to graft tissues from one person to another which will survive for periods of a year or more. Kidneys have been successfully transplanted between non-identical twins. Heart and lung transplants have been reasonably successful in animals, though rejection problems in humans have yet to be solved. “Spare parts” surgery, the simple routine replacement of all worn-out organs by new ones, is still a dream of the distant future. As yet, surgery is not ready for such miracles. In the meantime, you can be happy if your doctor says to you,“Yes, I think it is possible to operate on you for this condition.” Questions: What’s the main difficulty in organ transplanting