听力原文： Do you know what Prince Charles, Seve Ballesteros and Elizabeth Taylor have in common? They all suffer from chronic back pain. In fact, bad back is one of the most common health problems today, affecting people in all walks of life. The most recent available figures show that about a quarter of a million people are incapacitated with back pain every day. And many sufferers don't know the cause or the solution to their problem. The majority of our patients at the clinic tend to be women. They are especially vulnerable because of pregnancy but also because of osteoporosis, which I personally believe to be the major cause of problems for women. I have many women patients who say they have completely given up exercise because the pain makes them so miserable. But of course that starts up a vicious circle. Bed rest, giving up exercise and pain killers are traditional responses to back pain but, although there are many excellent drugs on the market, at our clinic we are beginning to realise the unique benefits of relaxation therapy. Other specialists in the field make a strong case for certain types of exercise, but in our experience they are easily mishandled and can lead to more harm than good. Now, let's look at some of the reasons why back pain is developing into such a unique menace. In general, the body is pretty good at self-repair. A strain or a blow to a limb, though painful at the time, generally resolves itself. But the body's response to back injury can be very counter-productive. When pain strikes, we attempt to keep the back as immobile as possible, which makes the muscles tense up. Research shows that they often go into spasm, which cause further twisting of the spine. A vicious circle is underway. The second mistake we often make when stricken with extreme back pain is to go to bed and stay there. Although at the clinic we recognise that a short rest in bed can be helpful… up to two days… any longer makes our back muscles become weaker and unable to hold up our spine. The pain therefore becomes worse. Another problem is being overweight. Anyone a stone or more overweight who already has back pain is not doing himself any favours: though it won't actually set it off in the first place, the weight will increase the strain and make things worse. The British diet could be partially to blame for the increase in back pain: over the last ten years the average weight of men has risen by 11 lbs. and of women by 9 lbs.. Questions: 16.What is the speaker mainly talking about? 17.According to the speaker, what is the main cause of back pain in women? 18.What does the clinic mainly recommend as treatment for back pain? 19.What is the main difference between back and other parts of the body? 20.According to the speaker, which of the following statements about bed rest is true? (36)