雅思阅读模拟练习题(6)

　　雅思考试前，我们总会做大量的模拟练习题来训练自己的英语能力，在做题中提升自己的雅思考试解题技巧~新东方在线雅思网今天为大家准备了雅思阅读模拟练习题(6)，正在雅思备考的你可千万别错过，要认真练习哟~

　　You should spend about 20 minutes on questions 14-26, which are based on Reading Passage 2 below.

　　Question 14

　　Choose the most suitable title for Reading passage 2 from the list below. Write your answer in box 14 on your answer sheet.

　　A Old Remedies Still Work Today.

　　B The Forest Pharmacy.

　　C Miracle Cure From Nature.

　　D A Modern Cure For An Ancient Killer

　　A

　　The search for cures to treat common diseases is not new, nor is it unusual to find the cures for such diseases in tree bark. Aspirin for headaches and quinine for the treatment of malaria are both examples of modern medicines which have been derived from tree bark. But the latest additions to this list may be the most significant yet, according to the findings of research into the medicinal benefits of the bark of the African Bush Willow. At an international conference, Dr Scott Remick of the USA claimed that combretastin, a product of this bark, has proved up to 85% effective in combating cancer, and may, in combination with chemotherapy, finally provide a way to destroy many types of tumour.

　　B

　　The African Bush Willow, which grows in South Africa, has been recognised as a medicinal plant by local tribespeople for many years. In the past, its roots were used as purgatives and its gum was used to treat sores and ulcers. Common along river banks in southern Africa, this plant (scientific name, Combretum caffrum) has proved both hardy and prolific, It is one of the world's fastest-growing trees and can grow one metre in height annually to a maximum of fourteen metres. To sustain this level of growth normally requires warmth, rich soil and abundant water. but even when these are in short supply, the African Bush Willow can survive. It is resistant to severe drought and even sustained periods of frost, and temperatures well below zero do not damage the tree.

　　C

　　Combretastin, the active ingredient in the bark, was originally isolated form the stems and branches in the 1970a by South African researcher, Dr Gordon Cragg. A massive seventy-seven kilogrammes of material was needed from the tree to produce just a few milligrams of the active ingredient. However, scientists have now been able to produce the drug synthetically. This type of manufacturing has meant that the drug can now be mass-produced and used much more widely in the treatment of cancer. Most cancers are caused by tumours, which create their own network of capillaries to supply the blood they need in order to grow. The effect of combretastin is to reduce the tumour's ability to create these capillaries and thereby starve the tumour to death.

　　D

　　Combretastin appears to work very quickly, often reducing the blood flow to a tumour within four to six hours after its first application. A feature in its favour is that combretastin does not appear to affect the blood supplies to other healthy organs. But, used in isolation, a small number of cancerous cells which appear able to live off normal blood supplies, appear to remain unaffected by combretastin, and radiation therapy is required to destroy these cells and remove the threat of cancer altogether.

　　E

　　Initial trials have been carried out on twenty-five patients in the USA. These have met with a remarkable measure of success. One 55-year-old man, suffering from a particularly aggressive form of thyroid cancer before treatment, has been cancer-free for two years following a course of the new drug. It is generally held that if a cancer does not return within two years of treatment, it has been cured. So far, other patients involved in the trials since then, including those with cancer of the bowel, have also remained clear of their cancers.

　　F

　　Trials in the UK have met with similar success, but have reported significant side effects, including diarrhoea and skin pain. In Britain, experts believe that the drug works best in conjunction with other therapies, including radiotherapy. The results of these combined treatments suggest that 85% of cancers could be totally eliminated, and similar trials are due to start in the USA. Dr Kate Law of the Cancer Research Campaign in London comments, "We will be watching the results of these trials with interest. On the face of it, these latest trials are very encouraging.

　　G

　　The drug has been greeted with enthusiasm by professionals and patients alike despite some of the experiments having limited success. One patient suffering from lung and liver cancers agreed to be one of the guinea pigs in the pharmaceutical trials. Fortunately he met with a degree of success in that his respiratory organs have been clear for over a year. However, this has not been the case with the other source of cancer and as yet the new drug has had no marked effect on it. Nevertheless, researchers are continuing in their quest to find a cure for all forms of cancers and they are confident that a breakthrough is on the horizon.