S对R是一种反驳,也就是不支持R的观点,R说的是失业率的高,而S说的则是低,SO,IT IS OBVIOUSLY TO CONCLUDE THE ANSWER C THAT At exceptionally low levels of unemployment, Sharon’s argument suggests that choice C is likely to be false, so C is not assumed IS WRONG!
选B是没有问题的,但是我认为A也挺有道理的,如果对其进行取非既normal levels of unemployment are NOT rarely exceeded.也就是说会被超过~!那ROLAND的话就可以成立而不是什么EXAGGERATION啦~!那么SHARON的话就会被WEAKEN呀~!