102. Although migraine headaches are believed to be caused by food allergies, putting patients on diets that eliminate those foods to which the patients have been demonstrated to have allergic migraine reactions frequently does not stop headaches. Obviously, some other cause of migraine headaches besides food allergies much exist.
Which of the following, if true, would most weaken the conclusion above?
(A) Many common foods elicit an allergic response only after several days, making it very difficult to observe links between specific foods patients eat and headaches they develop.
(B) Food allergies affect many people who never develop the symptom of migraine headaches.
(C) Many patients report that the foods that cause them migraine headaches are among the foods that they most enjoy eating.
(D) Very few patients have allergic migraine reactions as children live migraine-free adult lives once they have eliminated from their diets foods to which they have been demonstrated to be allergic.
(E) Very rarely do food allergies cause patients to suffer a symptom more severe than that of migraine headaches.
102.
If it is difficult to determine which foods cause migraines, then some foods that cause allergic reactions might not have been demonstrated to do so. Hence, if choice A is true, eliminating foods that have been demonstrated to cause migraines might not eliminate migraines, even if food allergies are the only cause of migraines. Choice A is the best answer.
Neither the fact some food allergies do not result in migraines (choice B), nor the fact that few allergies result in symptoms more severe than migraines. Choice C suggests that migraine suffers do not naturally avoid the foods at issue. Choice D reiterates the information that eliminating certain foods does not usually solve the problem.
我的理解：原题的conclusion是：除了food allergies还有别的原因；
那么weak 这一观点的选项应该是说只有food allergies 是 only cause
那为什么是A 呢？请指教 | 
