私醫聯招 英文歷屆試題｜第 273 題

The human brain is a remarkably complex organic computer, taking in  (21)  sensory experiences, processing and storing this information, and recalling and integrating selected bits at the right moments. The destruction  (22)  by Alzheimer's disease has been likened to the erasure of a hard drive, beginning with the most recent files and working backward. As the illness progresses, old  (23)  new memories gradually disappear until even loved ones are no longer recognized. Unfortunately, the computer analogy  (24) ; one cannot simply reboot the human brain and reload the files and programs. The problem is that Alzheimer's disease does not only erase information; it destroys the very hardware of the brain, which  (25)  more than 100 billion nerve cells (neurons), with 100 trillion connections among them.