[解析]
(1)D.主旨大意题.根据文章第二段:Now American researchers think they are close to developing a pill,which will help people forget bad memories可知文章主要关于忘记不好的记忆一种方法;故选D.
(2)A.细节理解题.根据第三段:The drug stops the body releasing chemicals that fix memories in the brain可知在人身上测试的药物阻止身体的某些化学品生产;故选A.
(3)D.细节理解题.根据最后一段:All of us can think of bad events in our lives that were terrible at the time but make us who we are可知Rebecca Dresser同意经历坏事件使我们与众不同;故选D.
(4)B.推理判断题.根据第二段:So far the research has suggested that only the emotional effects of memories may be reduced,not that the memories are wiped out可知人们怀疑这个药的效果;故选B.